This work was supported by the UOIT start-up fund. We thank Mr. Matthew Baxter (UOIT) for his assistance in the laboratory.

1. Síntesis de Ynone <ol><li> Utilizando una balanza analítica, pesar 0,15 mmol de la sal de potasio alkynyltrifluoroborate deseado (1,5 equivalentes) y se añade a un vial limpio equipado con una barra de agitación magnética. </li><li> El uso de un émbolo de la jeringa de vidrio equipado con una aguja, añadir 0,5 ml de DCM anhidro para el vial para proporcionar una solución de 0,3 M trifluoroborato. NOTA: Como se trata de una nueva metodología, se han realizado las reacciones de prueba de concepto. Con el fin de reducir los residuos que se han realizado en una pequeña escala. La reacción puede hacerse a escala para producir mayores rendimientos según sea necesario. </li><li> Usando una jeringa de vidrio, añadir 0,15 mmol de una solución de tricloruro de boro 1,0 M (1,5 equivalentes, 150 ml) gota a gota al recipiente de reacción a temperatura ambiente (20 ° C) con agitación. Reemplace la tapa. Retener o sujetar el recipiente de reacción tapado de tal manera que la solución de reacción está por debajo de la línea de agua en el baño de ultrasonidos. Sonicar la solución durante 30 segundos a 20 ° C y una o frecuenciaf 40 kHz. </li><li> Se agita la solución de reacción a temperatura ambiente (20 ° C) durante un adicional de 20 min. Dependiendo de la naturaleza del material de partida alkynyltrifluoroborate, observar un cambio de color. Un cambio de color de blanco a marrón claro o marrón oscuro, rojo o púrpura es común. </li><li> Añadir 0,1 mmol del cloruro de acilo deseado (1,0 equivalente) en el vial a temperatura ambiente (20 ° C) con agitación. Alternativamente, transferir el contenido del recipiente de reacción a un matraz cargado con una barra de agitación magnética y 0,1 mmol de cloruro de acilo. Reemplace la tapa. Se agita la solución de reacción a temperatura ambiente (20 ° C) durante 30 min. NOTA: Por lo general, un cambio a un color muy oscuro es una indicación de que la reacción está teniendo lugar. </li><li> Usando una cromatografía en capa fina (TLC) 34 supervisar el progreso de la reacción mediante la comparación con el estándar de cloruro de acilo apropiado. NOTA: En función de la naturaleza de los materiales de partida, la reacción no puede llegar a su finalización. La unamaterial de partida cloruro de cilindros se ha observado como un punto de funcionamiento más alta que el producto final para todos los ynones preparados hasta la fecha usando este método. <ol><li> Preparar el estándar de cloruro de acilo mediante la dilución de aproximadamente 10 mg de cloruro de acilo material de partida con 1 ml de acetato de etilo en un pequeño vial. </li><li> El uso de un observador de tiro TLC, detectar la solución de reacción y la serie en la línea de salida de la placa de TLC. Un co-spot tanto con la solución de reacción y el nivel puede ser útil para determinar si hay material presente en la solución de reacción todavía de partida. </li><li> Determinar una fase móvil TLC adecuado por ensayo y error. Para la preparación de producto 1a, una fase móvil que consiste en 01:30 acetato de etilo: hexanos resultados en los valores de R f de aproximadamente 0,5 y 0,8 para el producto ynone y cloruro de benzoilo material de partida, respectivamente. </li><li> Visualice la placa de TLC desarrollado bajo la luz ultravioleta. Use un lápiz para marcar las manchas visibles. </li></ol></li></ol> 2. acuosa Workup <ol><li> Interrumpir la reacción mediante la adición de 1 ml de agua fría (aproximadamente 5 ° C) al recipiente de reacción. Utilizando una pipeta Pasteur, transferir la solución a un embudo de separación limpia. Además diluir el contenido del embudo de decantación con 10 ml de agua fría y extraer el producto una vez en 15 ml de acetato de etilo. </li><li> Desechar la capa acuosa inferior y se lava la capa orgánica una vez adicional con 10 ml de agua y una vez con 10 ml de salmuera. Recoger la fase orgánica en un matraz Erlenmeyer limpia y seca con sulfato de magnesio. Filtrar la solución en un matraz de fondo redondo limpio usando filtración por gravedad. </li></ol> 3. Purificación de Ynone <ol><li> El uso de cromatografía de capa fina, determinar una fase móvil adecuado para la purificación cromatografía ultrarrápida del producto. Un factor de retención (R f) de aproximadamente 0,5 es generalmente suficiente para separar el producto de cualquier inicio restanteing materiales y productos secundarios. NOTA: En el caso de una mala separación, un sistema disolvente menos polar puede ser utilizado de tal manera que el producto tiene un valor R f inferior. Dependiendo de la polaridad de los materiales de partida, una mezcla de hexanos: acetato de etilo en el intervalo de 30: 1 a 5: 1 es generalmente adecuada. </li><li> Preparar una columna que contiene sílice húmeda con la fase móvil adecuada. Añadir una capa de arena de la parte superior de la columna con el fin de evitar molestar a la sílice después de la adición del producto y eluyente. </li><li> Evaporar la solución estudio diagnóstico usando un evaporador rotatorio con la temperatura del baño a 40 ° C y la rotación ajustado a 120 rpm. Disolver el contenido del matraz en un 2 ml de fase móvil y cargar cuidadosamente la solución de manera uniforme en la columna. Asegúrese de que la sílice está mojado pero la línea de disolvente no excede la altura de la sílice. Permitir algún disolvente para eluir tal que el producto se encuentra en la sílice. Agregue una pequeña cantidad de la fase móvil y repetir. </li><li> Llene el colUMN con la fase móvil determinado en el paso 3.1; en el caso de producto 1a, una 30: 1 mezcla de hexanos: acetato de etilo es apropiado. Reunir las fracciones en tubos de ensayo, usando la cromatografía flash para acelerar el proceso de purificación. Sólo tienes que conectar un adaptador con un tubo a una salida de aire. Ajustar la presión de aire de tal manera que el eluyente fluye a través de la columna a una velocidad adecuada. </li><li> Detectar cada una de las fracciones de la columna en una placa de TLC. Opcionalmente, detectar el estándar de cloruro de acilo como referencia. Desarrollar el TLC utilizando la fase móvil se considere apropiado en el paso 1.8. Marque los puntos visibles bajo luz ultravioleta, y señaló que se espera que el producto tenga un Rf más bajo que el estándar de cloruro de acilo. </li><li> Recoge todas las fracciones que contenían manchas visibles en un gran matraz de fondo redondo. Si más de un punto con un Rf menor que el material de partida está presente, recogerlos en frascos separados. Se evapora el disolvente utilizando un evaporador rotatorio y se seca el material recogido under alto vacío durante dos horas. </li><li> Si es necesario, realizar un lavado de pentano en una pequeña columna con el fin de purificar adicionalmente un producto preparado a partir de un ynone pobre material de partida cloruro de acilo de electrones. A pequeña escala, esto puede llevarse a cabo utilizando una pipeta Pasteur como la columna. <ol><li> Se disuelve el producto en una cantidad mínima de cloroformo, DCM, o éter dietílico y se carga en una columna de sílice húmeda con pentano. Eluir 1-2 longitudes de columna de pentano a través de la columna y recoger en un vaso de precipitados de residuos. </li><li> Eluir la ynone producto puro de la columna de pentano usando éter dietílico o acetato de etilo. Recoger eluyente en un matraz separado, se evapora, y se coloca bajo alto vacío durante un mínimo de dos horas. Obtener aproximadamente 10 mg de producto para la caracterización por espectroscopía de RMN. </li></ol></li></ol> 4. Caracterización de Ynone <ol><li> Caracterizar y evaluar la pureza del producto final usando 1 H y 13 C RMN espectroscopia. 34Típicamente, el desplazamiento químico del carbono del carbonilo aparece cerca de 177 ppm en el espectro de 13 C RMN. Los dos carbonos SP del grupo funcional ynone están representados por picos característicos cerca de 87 y 93 ppm. </li><li> Utilice la espectroscopia infrarroja 34 para identificar el pico carbonilo característica del producto ynone. Electron deslocalización de la triple enlace adyacente por lo general hace que el pico de carbonilo a aparecer entre 1600 y 1650 cm -1, en ​​función de las características electrónicas del compuesto. </li><li> Determinar la masa molecular del producto y validar la identidad mediante espectrometría de masas de alta resolución. 34 </li></ol>

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W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+student's+lab+companion:+laboratory+techniques+for+organic+chemistry:+standard+scale+and+microscale.">The student's lab companion: laboratory techniques for organic chemistry: standard scale and microscale.</a> Pearson College Div. , (2008).</li><li>Molander, G. A., Cavalcanti, L. N., Canturk, B., Pan, P. -. S., Kennedy, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+Hydrolysis+of+Organotrifluoroborates+via+Silica+Gel+and+Water.">Efficient Hydrolysis of Organotrifluoroborates via Silica Gel and Water.</a> 74, 7364-7369 (2009).</li><li>Molander, G. A., Ellis, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organotrifluoroborates:+protected+boronic+acids+that+expand+the+versatility+of+the+Suzuki+coupling+reaction.">Organotrifluoroborates: protected boronic acids that expand the versatility of the Suzuki coupling reaction.</a> Acc. Chem. Res. 40, 275-286 (2007).</li><li>Calloway, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Friedel-Crafts+Syntheses.">The Friedel-Crafts Syntheses.</a> Chem. Rev. 17, 327-392 (1935).</li><li>Gore, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Friedel-Crafts+acylation+reaction+and+its+application+to+polycyclic+aromatic+hydrocarbons.">The Friedel-Crafts acylation reaction and its application to polycyclic aromatic hydrocarbons.</a> Chem. Rev. 55, 229-281 (1955).</li><li>Groves, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Friedel&#8211;Crafts+acylation+of+alkenes.">The Friedel&#8211;Crafts acylation of alkenes.</a> Chem. Soc. Rev. 1, 73-97 (1972).</li><li>Kim, B. J., Matteson, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conversion+of+alkyltrifluoroborates+into+alkyldichloroboranes+with+tetrachlorosilane+in+coordinating+solvents.">Conversion of alkyltrifluoroborates into alkyldichloroboranes with tetrachlorosilane in coordinating solvents.</a> Angew. Chem. 116, 3118-3120 (2004).</li><li>Thompson, L., Doraiswamy, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonochemistry:+science+and+engineering.">Sonochemistry: science and engineering.</a> Ind. Eng. Chem. Res. 38, 1215-1249 (1999).</li></ol>

The authors declare that they have no competing financial interests.

La Tabla 1 ilustra las medidas adoptadas para optimizar las condiciones para la reacción de trifluoroborato fenilacetileno con cloruro de benzoilo para formar el producto ynone correspondiente. Inicialmente, los catalizadores conocidos para convertir organotrifluoroborates a organodifluoroboranes se probaron. Desafortunadamente gel de sílice, 35 tetracloruro de silicio, 36 y trifluoruro de boro 31,32 no promovió la formación de la ynone deseada (Tabla 1, entradas 1-3). El uso de catalizadores clorados ácidos de Lewis resultó ser más exitoso. Un bajo rendimiento de la ynone 1a deseado se obtuvo en presencia de un hierro (III) catalizador de cloruro de (Tabla 1, entrada 4). A continuación, cloruro de aluminio (III) se investigó como resultado de su capacidad bien establecida para promover la formación de iones Oxocarbenio en acilaciones de Friedel-Crafts. 37-39 El producto deseado se obtuvo con un rendimiento del 62% cuando un aluminio (III) catalizador de cloruro era empLoyed. La optimización adicional reveló que el aire y la humedad tienen poco efecto sobre el rendimiento de la reacción (Tabla 1, entradas 5-7). Como resultado, las reacciones posteriores se realizaron en material de vidrio no se seca en la presencia de aire. Los intentos para optimizar el disolvente revelaron que diclorometano (DCM) se adapta particularmente bien a la reacción (Tabla 1, entradas 8-12). Las inconsistencias en los resultados de las reacciones catalizadas por cloruro de aluminio (III) impulsaron la exploración de catalizadores alternativos. Comercialmente disponible de aluminio (III) hexahidrato de cloruro era completamente inactivo en las condiciones de reacción (Tabla 1, entrada 13). Este es un buen indicador de que la formación de cloruro de aluminio (III) hidrato inhibe la reacción. Tricloruro de boro se encontró para producir rendimientos similares con mejor consistencia (Tabla 1, entrada 14). Tras la interacción de la alkynyltriflu de potasiooroborate con tricloruro de boro, se forma una especie organodichloroborane más reactivos. 40 Este paso inicial es crítica para la reacción con el cloruro de acilo y la formación de la ynone para proceder. Desde sales organotrifluoroborate no son solubles en DCM, la reacción se lleva a cabo como una mezcla heterogénea. Después de la adición de tricloruro de boro, la solución se sometió a ultrasonidos para facilitar la formación de las especies reactivas dicloroborano mediante el aumento de la superficie de la sal de trifluoroborato disponible para reaccionar. La aplicación de ondas de ultrasonido a la mezcla de reacción provoca efectos mecánicos a través de la generación de burbujas de cavitación. Durante la sonicación, el colapso de las burbujas de cavitación en los resultados de fluidos en zonas localizadas de las altas temperaturas y presiones. 41 Las ondas de choque se producen turbulencias que crean microscópica resulta en un aumento en la energía cinética de las sales de trifluoroborato sólidos. El aumento en la energía del sistema durante promo sonicaciónTES fragmentación de la sal de trifluoroborato resultante aumentó área de superficie disponible para interactuar con tricloruro de boro. La sonicación de la mezcla de reacción antes de la adición del material de partida cloruro de acilo asegura la formación eficiente de las especies reactivas alkynyldichloroborane sin la necesidad de condiciones forzando más o tiempos de reacción más largos. La Figura 2 ilustra los resultados obtenidos cuando trifluoroborato fenilacetileno se hizo reaccionar con una variedad de cloruros de acilo bajo las condiciones de reacción optimizadas. Neutral aromático (1b, 1c) y alifáticos (1j-l) cloruros de acilo amueblar las ynones correspondientes en los rendimientos sintéticamente útiles. Estos cloruros de acilo que llevan grupos donadores de electrones (1d-g) proporcionan excelentes rendimientos mientras que los grupos aceptores de electrones resultan en rendimientos comparativamente modestos (1h, 1i, 1m). Interestingly, cuando el grupo aceptor de electrones se encuentra en la posición orto (1i, 59%), un aumento de rendimiento significativo se observa en comparación con el párrafo análogo sustituido cloruro de acilo (1h, 30%). La interacción estérica del sustituyente en la posición orto puede forzar el grupo funcional carbonilo fuera del plano, compensando así el carácter aceptor de electrones del anillo aromático. Vale la pena señalar que el cloruro de 4-bromobutirilo hace reaccionar para dar el producto deseado de 1 m con un rendimiento del 39%. Hasta donde sabemos, este es el primer protocolo para la síntesis de ynones tolerar un grupo funcional bromuro de alquilo. En ocasiones, cuando el cloruro de acilo material de partida es neutro o deficiente en electrones, impurezas alifáticos aparecen en la RMN de protón. Esto puede requerir un lavado de pentano con el fin de purificar adicionalmente el producto. Mientras sea posible, no es económico para llevar a cabo el lavado de pentano durante la primera etapa de purificación sInce pentano es costoso en comparación con hexanos. Completando la purificación secundaria por separado en una escala más pequeña tal como una columna pipeta Pasteur reduce significativamente la cantidad de pentano necesario. La Figura 3 ilustra el efecto de la identidad de la sal alkynyltrifluoroborate en el rendimiento de la reacción. En general, los derivados de sal de cojinete sustituyentes donadores de electrones del fenilacetileno trifluoroborato en el anillo aromático se hacen reaccionar con cloruros de acilo aromáticos y alifáticos para producir los ynones deseados en rendimientos de buenos a excelentes (2a-c, 3a-c). Sales de alkynyltrifluoroborate alifáticos demostraron ser sustratos menos reactivos. Rendimientos modestos se han obtenido cuando hexynyl- y sales cyclopentylethynyltrifluoroborate se hicieron reaccionar con derivados ricos en electrones de cloruro de benzoilo (4a, 5a). En conclusión, un nuevo método para la preparación of ynones de cloruros de acilo y sales de potasio alkynyltrifluoroborate se ha desarrollado. Los rendimientos obtenidos para la síntesis de ynones por este rango método de modesto a excelente dependiendo de la naturaleza del cloruro de acilo y trifluoroborato materiales de partida. En general aquellos materiales de partida que llevan sustituyentes donadores de electrones se someten a la reacción más fácilmente que los materiales de partida que tienen grupos funcionales neutros y aceptores de electrones. El valor de este enfoque radica en la simplicidad y grupo funcional tolerancia operativa del método. Esto, la reacción de un solo recipiente sencillo procede rápidamente a temperatura ambiente en presencia de tricloruro de boro sin exclusión de aire y humedad. Este método conveniente se puede emplear en la preparación de ynones en modesta a los excelentes rendimientos de una variedad de cloruros de acilo y sales alkynyltrifluoroborate.

The intention of this video is to demonstrate a straightforward approach for the preparation of compounds containing an ynone functional group from convenient starting materials. Ynones are valuable building blocks in organic chemistry that have been shown to have biomedical and material significance. Ynones are precursors to valuable organic functional groups including pyrimidines,1,2 quinolones,3 furans,4 pyrazoles,5,6 flavones,7 oximes,8 and chiral propargylic alcohols.9-11 A more convenient method for the preparation of ynones has been sought as a result of the drawbacks of traditional methods including poor functional group tolerance and tedious synthetic routes.
The reaction of metal12,13 and metalloid14 acetylides with acyl chlorides is one common route for the preparation of ynones. Alternatively, the synthesis of ynones from acyl chloride can be achieved via two-step procedures using Weinreb amides and organolithium or Grignard reagents.15 Another prevalent approach includes the addition of organolithium or Grignard reagents to an aldehyde, which is followed by the oxidation of a secondary alcohol to the corresponding ketone.16-19 Poor functional group tolerance of metal acetylides and the need to purify synthetic intermediates after each step are main deficiencies of the aforementioned methods. Transition-metal-catalyzed carbonylative couplings have recently emerged as an alternative approach for the preparation of ynones.20-22 Unfortunately, in addition to cost and toxicity associated with transition metals, metal-catalyzed carbonylative reactions often require elevated CO pressures and suffer from the presence of an undesired Sonogashira coupling byproduct. Given their utility in organic synthesis as well as the drawbacks associated with traditional synthetic methods, the development of a more straightforward method for the preparation of ynones is appealing.
Potassium organotrifluoroborate salts have recently emerged as versatile reagents in organic synthesis. Advantages including ease of preparation,23 inherent stability, low toxicity, and good functional group tolerance have made organotrifluoroborate salts attractive synthetic reagents.24-27 Organotrifluoroborate salts have been used primarily as a bench-stable equivalent of boronic acids for palladium-catalyzed Suzuki-Miyaura coupling.26 Recently, following a seminal work by Matteson and co-workers,28 Bode, Molander and others have highlighted the utility of organotrifluoroborates as reagents in non-metal catalyzed reactions.29-33 The field of transition-metal-free reactions of trifluoroborates is still in its infancy stage. Given the great potential for use of organotrifluoroborate salts in non-metal catalyzed organic synthesis, we sought to develop a novel method for the preparation of ynones from acyl chlorides and alkynyltrifluoroborate salts.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:71px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sonicator</td>
			<td style="width:71px;">VGT</td>
			<td style="width:119px;">1860QT</td>
			<td>Ultrasonic cleaner. Similar sonication devices may be used.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dichloromethane</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">270997</td>
			<td>Anhydrous</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Boron trichloride solution&#160;</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">178934</td>
			<td>1M solution in DCM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acyl chloride</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">Various</td>
			<td>Acyl chlorides from other suppliers such as Alfa Aesar may be used. Caution - refer to MSDS for safety information.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Potassium alkynyltrifluoroborate salt</td>
			<td style="width:71px;">N/A</td>
			<td style="width:119px;">N/A</td>
			<td>Synthesized23 from terminal alkyne</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethyl acetate</td>
			<td style="width:71px;">ACP</td>
			<td style="width:119px;">E-2000</td>
			<td>ACS grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hexanes</td>
			<td style="width:71px;">ACP</td>
			<td style="width:119px;">H-3500</td>
			<td>ACS grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pentane</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">236705</td>
			<td>Anhydrous</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Magnesium sulfate</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">M7506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Filter paper</td>
			<td style="width:71px;">Whatman</td>
			<td style="width:119px;">1093 126</td>
			<td>Student grade. This speceific variety is not necessary.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Silica Gel 60</td>
			<td style="width:71px;">EMD</td>
			<td style="width:119px;">1.11567.9026</td>
			<td>Particle size 0.040-0.063</td>
		</tr>
	</tbody>
</table>

metal-free synthesis of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups and scaffolds. Traditional methods for the preparation of ynones are associated with drawbacks including harsh conditions, multiple purification steps, and the presence of unwanted byproducts. An alternative method for the straightforward preparation of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts is described herein. The adoption of organotrifluoroborate salts as an alternative to organometallic reagents for the formation of new carbon-carbon bonds has a number of advantages. Potassium organotrifluoroborate salts are shelf stable, have good functional group tolerance, low toxicity, and a wide variety are straightforward to prepare. The title reaction proceeds rapidly at ambient temperature in the presence of a Lewis acid without the exclusion of air and moisture. Fair to excellent yields may be obtained via reaction of various aryl and alkyl acid chlorides with alkynyltrifluoroborate salts in the presence of boron trichloride.

Los esfuerzos iniciales se centraron alrededor de la preparación de ynone 1a de trifluoroborato fenilacetileno S1 y cloruro de benzoilo (Figura 1). La Tabla 1 ilustra los pasos de optimización desempeñadas incluida la detección de varios ácidos de Lewis, disolventes, así como el examen del efecto del agua sobre la reacción de . A continuación, el ámbito de aplicación de la reacción ha sido explorado por la presentación de trifluoroborato fenilacetileno a las condiciones optimizadas en la presencia de una variedad de cloruros de acilo (Figura 2). Modest a excelentes rendimientos se pueden obtener dependiendo de la naturaleza del sustrato cloruro de acilo. El alcance de la reacción adicional se ha evaluado a través de la preparación de varios ejemplos adicionales de sales de alkynyltrifluoroborate. La figura 3 ilustra ejemplos seleccionados de otras sales alkynyltrifluoroborate que se pueden emplear en la preparación de ynones en las condiciones desarrolladas. Los derivados de phenylacetylene electrones rodamiento trifluoroborato sustituyentes donantes que ofrecen los productos ynone correspondientes en buenos a excelentes rendimientos mientras que los derivados alifáticos de sales alkynyltrifluoroborate demostraron ser poco menos reactivos que ofrezcan rendimientos modestos. <img alt="Figura 1" src="/files/ftp_upload/52401/52401fig1highres.jpg" /> Figura 1: Preparación de Ynone 1a de trifluoroborato fenilacetileno S1 y cloruro de benzoilo Esquema que ilustra las condiciones para la preparación de ynone 1a incluyendo la formación de la dicloroborano intermedio reactivo.. <img alt="Figura 2" src="/files/ftp_upload/52401/52401fig2highres.jpg" /> Figura 2:. Representante 1 H espectro de RMN de ynone 1a desplazamientos químicos y las integraciones relativas de protones característicos están marcados. Figura 3:. Representante 13 C espectro de RMN de ynone 1a desplazamientos químicos de los carbonos característicos están etiquetados. <img alt="Figura 4" src="/files/ftp_upload/52401/52401fig4highres.jpg" /> Figura 4:. Espectro HRMS Representante de ynone 1a obtenida a través de la ionización química a presión atmosférica El valor m / z medida del [M + H] + iones son declarados. <img alt="Figura 5" src="/files/ftp_upload/52401/52401fig5highres.jpg" /> Figura 5: Reacciones de sal phenylacetylenetrifluoroborate S1 con cloruros de acilo Estructuras y de los rendimientos de los productos producidos por la variación de la identidad.del material de partida cloruro de acilo se ilustran. Las reacciones se realizaron con 1 equiv de cloruro de acilo, 1,5 equiv S1 phenylacetylenetrifluoroborate potasio, y tricloruro de boro 1,5 equiv. <img alt="Figura 6" src="/files/ftp_upload/52401/52401fig6highres.jpg" /> Figura 6:. Reacciones de varios alkynyltrifluoroborates con cloruros de acilo Estructuras y los rendimientos para los productos producidos por la variación de la identidad del material de partida se ilustra alkynyltrifluoroborate. Las reacciones se realizaron con 1 equiv de cloruro de acilo, 2,5 equiv sal de potasio organotrifluoroborate y tricloruro de boro 2,5 equiv. <table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> Entrada </td><td> Ácido de Lewis </td><td> Ácido de Lewis (equiv) </td><td> Condiciones </td><td> Rendimiento (%) </td></tr><tr><td> 1 b &lt;/ Sup&gt; </td><td> SiO 2 </td><td> 16.5 </td><td> CH 2 Cl 2 </td><td> 0 </td></tr><tr><td> 2 </td><td> SiCl4 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> rastro </td></tr><tr><td> 3 </td><td> BF3 · OEt 2 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> rastro </td></tr><tr><td> 4 b </td><td> FeCl3 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 24 </td></tr><tr><td> 5 c </td><td> AlCl3 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 62 </td></tr><tr><td> 6 d </td><td> AlCl3 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 66 </td></tr><tr><td> 7 e </td><td> AlCl3 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 60 </td></tr><tr><td> 8 </td><td> AlCl3 </sub&gt; </td><td> 1 </td><td> THF </td><td> rastro </td></tr><tr><td> 9 </td><td> AlCl3 </td><td> 1 </td><td> tolueno </td><td> rastro </td></tr><tr><td> 10 </td><td> AlCl3 </td><td> 2 </td><td> ClCH2 CH 2 Cl </td><td> 33 </td></tr><tr><td> 11 </td><td> AlCl3 </td><td> 1 </td><td> DMSO </td><td> rastro </td></tr><tr><td> 12 </td><td> AlCl3 </td><td> 2 </td><td> acetonitrilo </td><td> rastro </td></tr><tr><td> 13 </td><td> AlCl3 · 6H 2 O </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 0 </td></tr><tr><td> 14 b </td><td> BCl3 </td><td> 1.5 </td><td> CH 2 Cl 2 </td><td> 67 </td></tr><tr><td> 15 </td><td> BBr 3 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 20 </td></tr></tbody></table><strong&gt; Tabla 1:. Optimización de las condiciones para la preparación de ynone 1a un rendimiento de producto 1a en la variación de condiciones de reacción y el catalizador ácido de Lewis. A las reacciones se realizaron con cloruro de benzoilo y 1 equiv 1 equiv phenylacetylenetrifluoroborate de potasio S1. B 1.5 equiv S1. C condiciones anhidras. D La reacción se llevó a cabo en material de vidrio no se secó bajo aire. E condiciones anhidras + 1 l de agua.

Watch this Scientific Journal Video about Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts at JoVE.com

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

The goal of this manuscript is to demonstrate a straightforward method for the preparation of ynones from acyl chloride and potassium alkynyltrifluoroborate salt starting materials. The one-pot reaction proceeds rapidly in the presence of boron trichloride without exclusion of air and moisture.

Sin metal Síntesis de Ynones de Acil cloruros y potasio Alkynyltrifluoroborate Sales

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups ...

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11.1K vistas.  University of Ontario Institute of Technology. The goal of this manuscript is to demonstrate a straightforward method for the preparation of ynones from acyl chloride and potassium alkynyltrifluoroborate salt starting materials. The one-pot reaction proceeds rapidly in the presence of boron trichloride without exclusion of air and moisture.

Video: Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Preparation and Use of Samarium Diiodide (SmI2) in Organic Synthesis: The Mechanistic Role of HMPA and Ni(II) Salts in the Samarium Barbier Reaction

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of molecular iodine to samarium metal in THF.1,2-3 It is a mild and selective single electron reductant and its versatility is a result of its ability to initiate a wide range of reductions including C-C bond-forming and cascade or sequential reactions. SmI2 can reduce a variety of functional groups including sulfoxides and sulfones, phosphine oxides, epoxides, alkyl and aryl halides, carbonyls, and conjugated double bonds.2-12 One of the fascinating features of SmI-2-mediated reactions is the ability to manipulate the outcome of reactions through the selective use of cosolvents or additives. In most instances, additives are essential in controlling the rate of reduction and the chemo- or stereoselectivity of reactions.13-14 Additives commonly utilized to fine tune the reactivity of SmI2 can be classified into three major groups: (1) Lewis bases (HMPA, other electron-donor ligands, chelating ethers, etc.), (2) proton sources (alcohols, water etc.), and (3) inorganic additives (Ni(acac)2, FeCl3, etc).3
Understanding the mechanism of SmI2 reactions and the role of the additives enables utilization of the full potential of the reagent in organic synthesis. The Sm-Barbier reaction is chosen to illustrate the synthetic importance and mechanistic role of two common additives: HMPA and Ni(II) in this reaction. The Sm-Barbier reaction is similar to the traditional Grignard reaction with the only difference being that the alkyl halide, carbonyl, and Sm reductant are mixed simultaneously in one pot.1,15 Examples of Sm-mediated Barbier reactions with a range of coupling partners have been reported,1,3,7,10,12 and have been utilized in key steps of the synthesis of large natural products.16,17 Previous studies on the effect of additives on SmI2 reactions have shown that HMPA enhances the reduction potential of SmI2 by coordinating to the samarium metal center, producing a more powerful,13-14,18 sterically encumbered reductant19-21 and in some cases playing an integral role in post electron-transfer steps facilitating subsequent bond-forming events.22 In the Sm-Barbier reaction, HMPA has been shown to additionally activate the alkyl halide by forming a complex in a pre-equilibrium step.23
Ni(II) salts are a catalytic additive used frequently in Sm-mediated transformations.24-27 Though critical for success, the mechanistic role of Ni(II) was not known in these reactions. Recently it has been shown that SmI2 reduces Ni(II) to Ni(0), and the reaction is then carried out through organometallic Ni(0) chemistry.28
These mechanistic studies highlight that although the same Barbier product is obtained, the use of different additives in the SmI2 reaction drastically alters the mechanistic pathway of the reaction. The protocol for running these SmI2-initiated reactions is described.

Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

A straightforward procedure for the preparation of samarium diiodide (SmI2) in THF is described. The role of two main additives namely hexamethylphosphoramide (HMPA) and Ni(acac)2 in Sm mediated reactions is demonstrated in the Sm-Barbier reaction.

Preparación y uso de samario diyoduro (SMI<sub&gt; 2</sub&gt;) En Síntesis Orgánica: La función mecánica de HMPA y sales de Ni (II) en la reacción de samario Barbier

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of ...

Investigación

Química

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization

The traditional strategy for the introduction of chemical functionalities is the use of solid-phase synthesis by appending suitably modified phosphoramidite precursors to the nascent chain. However, the conditions used during the synthesis and the restriction to rather short sequences hamper the applicability of this methodology. On the other hand, modified nucleoside triphosphates are activated building blocks that have been employed for the mild introduction of numerous functional groups into nucleic acids, a strategy that paves the way for the use of modified nucleic acids in a wide-ranging palette of practical applications such as functional tagging and generation of ribozymes and DNAzymes. One of the major challenges resides in the intricacy of the methodology leading to the isolation and characterization of these nucleoside analogues.
	
	In this video article, we present a detailed protocol for the synthesis of these modified analogues using phosphorous(III)-based reagents. In addition, the procedure for their biochemical characterization is divulged, with a special emphasis on primer extension reactions and TdT tailing polymerization. This detailed protocol will be of use for the crafting of modified dNTPs and their further use in chemical biology.

The protocol described herein aims to explain and abridge the numerous obstacles in the way of the intricate route leading to modified nucleoside triphosphates. Consequently, this protocol facilitates both the synthesis of these activated building-blocks and their availability for practical applications.

Nucleósidos Trifosfatos - De la síntesis a la Caracterización bioquímica

The  traditional strategy for the introduction of chemical functionalities is the  use of solid-phase synthesis by appending suitably modified ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Síntesis y caracterización de supramoleculares Coloides

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. Detailed and generalized protocols are also presented for testing the catalytic activity of such complexes in arylation and Suzuki-Miyaura cross-coupling reactions. Representative results are shown for the catalytic activity of the four complexes in arylation and Suzuki-Miyaura type reactions. For each of the reactions investigated, at least one of the four complexes successfully catalyzed the reaction, qualifying them as promising candidates for catalysis of many carbon-carbon bond-forming reactions. The protocols presented are general enough to be adapted for the synthesis, purification and catalytic activity testing of new palladium N-heterocyclic carbene complexes.

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. The complexes were tested for catalytic activity in arylation and Suzuki-Miyaura reactions. For each reaction investigated, at least one of the four complexes successfully catalyzed the reaction.

Paladio<em&gt; N</em&gt; -Heterocíclicos de los complejos de carburo: Síntesis a partir de sales de benzimidazolio y actividad catalítica en las reacciones de formación de enlaces carbono-carbono

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have been thought of as a type of molecular information storage. Mass spectrometry analysis has been considered the method of choice for sequencing peptoids. Peptoids can be synthesized via solid phase chemistry using a repeating two-step reaction cycle. Here we present a method to manually synthesize oligo-peptoids and to analyze the sequence of the peptoids using tandem mass spectrometry (MS/MS) techniques. The sample peptoid is a nonamer consisting of alternating N-(2-methyloxyethyl)glycine (Nme) and N-(2-phenylethyl)glycine (Npe), as well as an N-(2-aminoethyl)glycine (Nae) at the N-terminus. The sequence formula of the peptoid is Ac-Nae-(Npe-Nme)4-NH2, where Ac is the acetyl group. The synthesis takes place in a commercially available solid-phase reaction vessel. The rink amide resin is used as the solid support to yield the peptoid with an amide group at the C-terminus. The resulting peptoid product is subjected to sequence analysis using a triple-quadrupole mass spectrometer coupled to an electrospray ionization source. The MS/MS measurement produces a spectrum of fragment ions resulting from the dissociation of charged peptoid. The fragment ions are sorted out based on the values of their mass-to-charge ratio (m/z). The m/z values of the fragment ions are compared against the nominal masses of theoretically predicted fragment ions, according to the scheme of peptoid fragmentation. The analysis generates a fragmentation pattern of the charged peptoid. The fragmentation pattern is correlated to the monomer sequence of the neutral peptoid. In this regard, MS analysis reads out the sequence information of the peptoids.

A protocol is described for the manual synthesis of oligo-peptoids followed by sequence analysis by mass spectrometry.

Síntesis y análisis de espectrometría de masas de peptoides Oligo

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have ...

Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine

Amino alcohols are versatile compounds with a wide range of applications. For instance, they have been used as chiral scaffolds in organic synthesis. Their synthesis by conventional organic chemistry often requires tedious multi-step synthesis processes, with difficult control of the stereochemical outcome. We present a protocol to enzymatically synthetize amino alcohols starting from the readily available L-lysine in 48 h. This protocol combines two chemical reactions that are very difficult to conduct by conventional organic synthesis. In the first step, the regio- and diastereoselective oxidation of an unactivated C-H bond of the lysine side-chain is catalyzed by a dioxygenase; a second regio- and diastereoselective oxidation catalyzed by a regiodivergent dioxygenase can lead to the formation of the 1,2-diols. In the last step, the carboxylic group of the alpha amino acid is cleaved by a pyridoxal-phosphate (PLP) decarboxylase (DC). This decarboxylative step only affects the alpha carbon of the amino acid, retaining the hydroxy-substituted stereogenic center in a beta/gamma position. The resulting amino alcohols are therefore optically enriched. The protocol was successfully applied to the semipreparative-scale synthesis of four amino alcohols. Monitoring of the reactions was conducted by high performance liquid chromatography (HPLC) after derivatization by 1-fluoro-2,4-dinitrobenzene. Straightforward purification by solid-phase extraction (SPE) afforded the amino alcohols with excellent yields (93% to &#62;95%).

Chiral amino alcohols are versatile molecules for use as scaffolds in organic synthesis. Starting from L-lysine, we synthesize amino alcohols by an enzymatic cascade reaction combining diastereoselective C-H oxidation catalyzed by dioxygenase followed by cleavage of the carboxylic acid moiety of the corresponding hydroxyl amino acid by a decarboxylase.

Reacciones de la cascada enzimática para la síntesis de aminoalcoholes quirales de L-lisina

Amino alcohols are versatile compounds with a wide range of applications. For instance, they have been used as chiral scaffolds in organic synthesis. ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

Síntesis de nanocables de Au sustrato enlazado mediante un mecanismo activo crecimiento superficial

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of their interactions with cell membranes, lipid bilayers, and viruses. The hydrophilic ligands make these particles colloidally stable in aqueous solutions and the combination with hydrophobic ligands creates an amphiphilic particle that can be loaded with hydrophobic drugs, fuse with the lipid membranes, and resist nonspecific protein adsorption. Many of these properties depend on nanoparticle size and the composition of the ligand shell. It is, therefore, crucial to have a reproducible synthetic method and reliable characterization techniques that allow the determination of nanoparticle properties and the ligand shell composition. Here, a one-phase chemical reduction, followed by a thorough purification to synthesize these nanoparticles with diameters below 5 nm, is presented. The ratio between the two ligands on the surface of the nanoparticle can be tuned through their stoichiometric ratio used during synthesis. We demonstrate how various routine techniques, such as transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectrometry, are combined to comprehensively characterize the physicochemical parameters of the nanoparticles.

Amphiphilic gold nanoparticles can be used in many biological applications. A protocol to synthesize gold nanoparticles coated by a binary mixture of ligands and a detailed characterization of these particles is presented.

Síntesis y caracterización de nanopartículas de oro anfifílicas

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of ...

Hierarchical and Programmable One-Pot Oligosaccharide Synthesis

This article presents a general experimental protocol for programmable one-pot oligosaccharide synthesis and demonstrates how to use Auto-CHO software for generating potential synthetic solutions. The programmable one-pot oligosaccharide synthesis approach is designed to empower fast oligosaccharide synthesis of large amounts using thioglycoside building blocks (BBLs) with the appropriate sequential order of relative reactivity values (RRVs). Auto-CHO is a cross-platform software with a graphical user interface that provides possible synthetic solutions for programmable one-pot oligosaccharide synthesis by searching a BBL library (containing about 150 validated and &#62;50,000 virtual BBLs) with accurately predicted RRVs by support vector regression. The algorithm for hierarchical one-pot synthesis has been implemented in Auto-CHO and uses fragments generated by one-pot reactions as new BBLs. In addition, Auto-CHO allows users to give feedback for virtual BBLs to keep valuable ones for further use. One-pot synthesis of stage-specific embryonic antigen 4 (SSEA-4), which is a pluripotent human embryonic stem cell marker, is demonstrated in this work.

This protocol demonstrates how to use the Auto-CHO software for hierarchical and programmable one-pot synthesis of oligosaccharides. It also describes the general procedure for RRV determination&#160;experiments and one-pot glycosylation of SSEA-4.

Síntesis jerárquica y programable de oligosacáridos de una olla

This article presents a general experimental protocol for programmable one-pot oligosaccharide synthesis and demonstrates how to use Auto-CHO software for ...

A Femtoliter Droplet Array for Massively Parallel Protein Synthesis from Single DNA Molecules

Advances in spatial resolution and detection sensitivity of scientific instrumentation make it possible to apply small reactors for biological and chemical research. To meet the demand for high-performance microreactors, we developed a femtoliter droplet array (FemDA) device and exemplified its application in massively parallel cell-free protein synthesis (CFPS) reactions. Over one million uniform droplets were readily generated within a finger-sized area using a two-step oil-sealing protocol. Every droplet was anchored in a femtoliter microchamber composed of a hydrophilic bottom and a hydrophobic sidewall. The hybrid hydrophilic-in-hydrophobic structure and the dedicated sealing oils and surfactants are crucial for stably retaining the femtoliter aqueous solution in the femtoliter space without evaporation loss. The femtoliter configuration and the simple structure of the FemDA device allowed minimal reagent consumption. The uniform dimension of the droplet reactors made large-scale quantitative and time-course measurements convincing and reliable. The FemDA technology correlated the protein yield of the CFPS reaction with the number of DNA molecules in each droplet. We streamlined the procedures about the microfabrication of the device, the formation of the femtoliter droplets, and the acquisition and analysis of the microscopic image data. The detailed protocol with the optimized low running cost makes the FemDA technology accessible to everyone who has standard cleanroom facilities and a conventional fluorescence microscope in their own place.

The overall goal of the protocol is to prepare over one million ordered, uniform, stable, and biocompatible femtoliter droplets on a 1 cm2 planar substrate that can be used for cell-free protein synthesis.