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

1. Síntese de Ynone <ol><li> Usando uma balança analítica, pesam 0,15 mmol de potássio desejado sal alkynyltrifluoroborate (1,5 equivalentes) e adicionar a um frasco limpo equipado com uma barra magnética. </li><li> Utilizando uma seringa de êmbolo de vidro equipada com uma agulha, adicionar 0,5 ml de DCM anidro para o frasco para se obter uma solução 0,3 M de trifluoroborato. NOTA: Uma vez que esta é uma nova metodologia, as reações têm sido realizadas para prova de conceito. De modo a reduzir o desperdício de terem sido realizados a uma escala pequena. A reacção pode ser dimensionado para produzir maiores rendimentos, conforme necessário. </li><li> Usando uma seringa de vidro, adicionar 0,15 mmol de 1,0 M de solução de tricloreto de boro (1,5 equivalentes, 150? L) gota a gota, ao vaso da reacção à temperatura ambiente (20 ° C) com agitação. Recoloque a tampa. Segurar ou prender o recipiente de reacção tapado de modo a que a solução de reacção é abaixo da linha de água no sonicador. Sonicar a solução durante 30 segundos a 20 ° C e a uma frequência of 40 kHz. </li><li> Agita-se a solução de reacção à temperatura ambiente (20 ° C) durante um adicional de 20 minutos. Dependendo da natureza do material de partida alkynyltrifluoroborate, observar uma mudança de cor. A mudança de cor do branco ao bege ou marrom escuro, vermelho ou roxo é comum. </li><li> Adicionar 0,1 mmol do cloreto de acilo desejado (1,0 equivalente) para o frasco à temperatura ambiente (20 ° C) com agitação. Alternativamente, transferir o conteúdo do vaso da reacção para um balão carregado com uma barra de agitação magnética e 0,1 mmol de cloreto de acilo. Recoloque a tampa. Agita-se a solução de reacção à temperatura ambiente (20 ° C) durante 30 min. NOTA: De um modo geral, uma mudança de uma cor muito escura é uma indicação de que a reacção está a ter lugar. </li><li> Usando uma cromatografia em camada fina (TLC) 34 monitorar o progresso da reacção por comparação com padrão de cloreto de acilo apropriado. NOTA: Dependendo da natureza dos materiais de partida, a reacção pode não ficar completa. A umcloreto cyl material de partida foi observada como um local de funcionamento mais elevada do que o produto final de todos os ynones preparados até à data usando este método. <ol><li> Prepare o padrão de cloreto de acilo por diluição de cerca de 10 mg do material de partida cloreto de acilo com 1 ml de acetato de etilo em um pequeno frasco. </li><li> Usando um spotter TLC, manchar a solução de reacção e o padrão na linha de partida da placa de TLC. Um co-mancha com tanto a solução de reacção e padrão podem ser úteis para determinar se existe ainda materiais presentes na solução da reacção de partida. </li><li> Determinar uma fase móvel adequada TLC por tentativa e erro. Para a preparação do produto 1a, uma fase móvel consistindo de 01:30 acetato de etilo: hexanos resulta em valores de Rf de cerca de 0,5 e 0,8 para o produto ynone e cloreto de benzoílo material de partida, respectivamente. </li><li> Visualize a placa TLC desenvolvido sob a luz UV. Use um lápis para marcar todos os pontos visíveis. </li></ol></li></ol> 2. O processamento aquoso <ol><li> Extingue-se a reacção por adição de 1 mL de água fria (cerca de 5 ° C) para o vaso de reacção. Usando uma pipeta de Pasteur, transferir a solução para um funil de separação limpa. Diluir o conteúdo do funil de decantação com 10 ml de água fria e extrai-se o produto uma vez em 15 ml de acetato de etilo. </li><li> Rejeitar a camada aquosa inferior e lava-se a camada orgânica uma vez adicional com 10 ml de água e uma vez com 10 ml de salmoura. Recolher a camada orgânica para um balão de Erlenmeyer limpo e seco com sulfato de magnésio. Filtrar a solução para um balão de fundo redondo limpo usando filtração por gravidade. </li></ol> 3. Purificação de Ynone <ol><li> Usando cromatografia de camada fina, determinar uma fase móvel adequada para purificação através de cromatografia do produto. Um factor de retenção (Rf) de cerca de 0,5 é geralmente suficiente para separar o produto a partir de qualquer partida remanescenteing produtos materiais e laterais. NOTA: No caso de uma separação deficiente, um sistema solvente menos polar pode ser utilizado de tal modo que o produto tem um valor Rf inferior. Dependendo da polaridade dos materiais de partida, uma mistura de hexanos: acetato de etilo no intervalo de 30: 1 a 5: 1 é geralmente adequado. </li><li> Prepara-se uma coluna contendo sílica gel húmida com a fase móvel adequada. Adicione uma camada de areia para a parte superior da coluna, a fim de evitar sílica perturbador após a adição do produto e eluente. </li><li> Evapora-se a solução de processamento utilizando um evaporador rotativo com a temperatura do banho a 40 ° C e a rotação definido para 120 rpm. Dissolve-se o conteúdo do balão em um 2 ml de fase móvel e carregar cuidadosamente a solução uniformemente sobre a coluna. Assegure-se que a sílica está molhado, mas a linha de solvente não exceda a altura da sílica. Permitir que algum solvente de eluição tais que o produto está na sílica. Adicionar uma pequena quantidade de fase móvel e repita. </li><li> Encha o column com a fase móvel determinado no passo 3.1; no caso do produto 1a, a 30: 1 hexanos: acetato de etila é apropriado. Recolher as fracções em tubos de ensaio, utilizando cromatografia flash, para acelerar o processo de purificação. Basta conectar um adaptador com tubulação para uma saída de ar. Ajustar a pressão do ar de tal modo que o eluente flui através da coluna a uma velocidade adequada. </li><li> Detectar cada uma das fracções da coluna numa placa de TLC. Opcionalmente, detectar o padrão de cloreto de acilo, tal como uma referência. Desenvolver o TLC com a fase móvel considerada adequada na etapa 1.8. Marque todos os pontos visíveis sob luz UV, lembrando que o produto é esperado para ter um R f mais baixa do que o padrão de cloreto de acila. </li><li> Recolha todas as frações contendo manchas visíveis em um balão de fundo redondo grande. Se mais de um local com um Rf inferior ao do material de partida está presente, recolher em frascos separados. Evapora-se o solvente usando um evaporador rotativo e secar o material recolhido under alto vácuo durante duas horas. </li><li> Se necessário, efectuar uma lavagem com pentano sobre uma pequena coluna de modo a purificar ainda mais um produto ynone preparado a partir de um material de má electrões de partida cloreto de acilo. Numa pequena escala, este pode ser realizado utilizando uma pipeta de Pasteur, como a coluna. <ol><li> Dissolve-se o produto numa quantidade mínima de clorofórmio, DCM, ou éter dietílico e de carga numa coluna de sílica húmido com pentano. Comprimentos Elute 1-2 coluna de pentano através da coluna e recolher em um copo de resíduos. </li><li> Eluir o produto ynone puro a partir da coluna usando pentano éter dietílico ou acetato de etilo. Recolhe eluente num balão separado, evapora-se, e colocar sob alto vácuo durante um mínimo de duas horas. Obter aproximadamente 10 mg de produto para caracterização por espectroscopia de RMN. </li></ol></li></ol> 4. Caracterização de Ynone <ol><li> Caracterizar e avaliar a pureza do produto final, utilizando 1 H e 13 C RMN espectroscopia. 34Tipicamente, o desvio químico de carbono do carbonilo aparece perto de 177 ppm no espectro de 13 C RMN. Os dois átomos de carbono SP do grupo funcional ynone são representados por picos característicos próximos 87 e 93 ppm. </li><li> Use espectroscopia de infravermelhos 34 para identificar o pico carbonilo característica do produto ynone. Electron deslocalização da ligação tripla adjacente normalmente faz com que o pico de carbonilo a aparecer entre 1.600 e 1.650 centímetros -1, dependendo das características do composto electrónicos. </li><li> Determinar a massa molecular do produto e ainda validar a identidade utilizando espectrometria de massa de alta resolução. 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.

A Tabela 1 ilustra os passos tomados para optimizar as condições para a reacção de fenilacetileno trifluoroborato com cloreto de benzoílo para formar o produto ynone correspondente. Inicialmente, catalisadores conhecidos para converter organotrifluoroborates para organodifluoroboranes foram testados. Infelizmente gel de sílica, 35 tetracloreto de silício, 36 e 31,32 de trifluoreto de boro não promover a formação do ynone desejado (Tabela 1, entradas 1-3). O uso de clorados catalisadores ácidos de Lewis provou ser mais bem sucedido. Um baixo rendimento do ynone 1a desejado foi obtido na presença de um catalisador de ferro (III), cloreto de (Tabela 1, entrada 4). Em seguida, alumínio (III), cloreto foi investigada como um resultado da sua capacidade bem estabelecido para promover a formação de iões oxocarbenium em acilações de Friedel-Crafts. 37-39 O produto desejado foi obtido com um rendimento de 62%, quando uma lata de alumínio (III), cloreto de catalisador foi employed. Optimização adicional revelou que o ar e a humidade tem pouco efeito sobre o rendimento da reacção (Tabela 1, entradas 5-7). Como resultado, as reacções subsequentes foram realizadas em material de vidro não seca na presença de ar. As tentativas para optimizar o solvente revelou que diclorometano (DCM) é particularmente bem adequado para a reacção (Tabela 1, entradas 8-12). Inconsistências nos resultados de reacções catalisadas por alumínio (III), cloreto de solicitado a exploração de catalisadores alternativos. Comercialmente disponível de alumínio (III) de hexahidrato de cloreto era completamente inactivo sob as condições de reacção (Tabela 1, entrada 13). Este é um bom indicador de que a formação de hidrato de alumínio (III), cloreto de inibe a reacção. Tricloreto de boro foi encontrado para produzir rendimentos similares com melhor consistência (Tabela 1, entrada 14). Após a interacção do potássio alkynyltrifluoroborate com tricloreto de boro, uma espécie organodichloroborane mais reactivos é formado. 40 Este passo inicial é crítica para a reacção com o cloreto de acilo e formação do ynone para prosseguir. Desde organotrifluoroborate sais não são solúveis em DCM, a reacção ocorre como uma mistura heterogénea. Depois da adição de tricloreto de boro, a solução é sonicada a fim de facilitar a formação das espécies reactivas dichloroborane aumentando a área de superfície do sal trifluoroborato disponível para reagir. Aplicação de ondas de ultra-sons à mistura de reacção provoca efeitos mecânicos, através da geração de bolhas de cavitação. Durante a sonicação, colapso de bolhas de cavitação nos resultados do fluido em áreas localizadas de altas temperaturas e pressões. 41 As ondas de choque são produzidas que criar turbulência microscópica resultando num aumento da energia cinética dos sais de trifluoroborato sólidos. O aumento da energia do sistema, durante sonificação promotes fragmentação do sal trifluoroborato resultante aumento da área de superfície disponível para interagir com tricloreto de boro. A sonicação da mistura de reacção antes da adição do material de partida cloreto de acilo garante uma formação eficiente das espécies reactivas alkynyldichloroborane sem a necessidade de condições de extracção ou mais tempos de reacção mais longos. A Figura 2 ilustra os resultados obtidos quando fenilacetileno trifluoroborato foi feito reagir com uma variedade de cloretos de acilo sob as condições de reacção optimizadas. Neutral aromático (1B, 1C) e alifáticos (1-J-l) cloretos de acila fornecer os ynones correspondentes em rendimentos sinteticamente úteis. Esses cloretos de ácido que comportam grupos doadores de electrões (1D-g) proporcionar excelentes rendimentos, enquanto os grupos electrões resultar em rendimentos relativamente modestos (1h, 1i, 1M). Interestingly, quando o grupo de remoção de electrões está localizado na posição orto (1i, 59%), um aumento do rendimento significativo é observado em comparação com o parágrafo análogo substituído de cloreto de acilo (1 h, 30%). A interacção estérica do substituinte na posição orto podem forçar o grupo funcional carbonilo para fora do plano, compensando assim o carácter de remoção de electrões do anel aromático. Vale a pena notar que o cloreto de 4-bromobutirilo reagiram para produzir o produto desejado 1m em 39% de rendimento. Para nosso conhecimento, esta é a primeira protocolo para a síntese de ynones para tolerar um grupo funcional brometo de alquilo. Ocasionalmente, quando o material de partida cloreto de acilo é neutro ou deficiente em electrões, impurezas alifáticos aparece na RMN de protões. Isto pode necessitar de uma lavagem com pentano de modo a purificar ainda mais o produto. Embora possível, não é económico para realizar a lavagem com pentano durante a primeira fase de purificação sesde pentano é caro em comparação com hexano. Completando a purificação secundária separadamente numa escala mais pequena, tal como uma coluna de uma pipeta de Pasteur reduz significativamente a quantidade de pentano necessária. A Figura 3 ilustra o efeito da identidade do sal alkynyltrifluoroborate sobre o rendimento da reacção. Em geral, os derivados do fenilacetileno trifluoroborato rolamento sal substituintes doadores de electrões no anel aromático reagir com cloretos de acilo aromáticos e alifáticos para produzir os ynones desejados com bons a excelentes rendimentos (2a-c, 3a-c). Sais alkynyltrifluoroborate alifáticos provaram ser substratos menos reactivos. Modestos rendimentos foram obtidos quando hexynyl- e sais cyclopentylethynyltrifluoroborate foram feitos reagir com derivados ricos em electrões de cloreto de benzoílo (4a, 5a). Em conclusão, um novo método para a preparação of ynones de cloretos de acilo e sais de potássio alkynyltrifluoroborate tem sido desenvolvido. Os rendimentos obtidos para a síntese de ynones por este método gama de modesta a excelente, dependendo da natureza do cloreto de acilo e trifluoroborato materiais de partida. Em geral esses materiais de partida que ostentam elétrons substituintes doadores de sofrer a reação mais facilmente do que matérias-primas que possuem grupos funcionais neutros e electrões. O valor desta abordagem reside na simplicidade e grupo funcional tolerância operacional do método. Este, reacção de um só recipiente simples procede rapidamente a temperatura ambiente na presença de tricloreto de boro sem exclusão de ar e humidade. Este método conveniente pode ser empregue na preparação de ynones em excelentes rendimentos modestos a partir de uma variedade de cloretos de acilo e sais 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.

Os esforços iniciais centraram-se em torno da preparação de ynone 1a de fenilacetileno trifluoroborato S1 e cloreto de benzoílo (Figura 1). A Tabela 1 ilustra os passos de optimização realizada, incluindo o rastreio de vários ácidos de Lewis, solventes, assim como o exame do efeito da água sobre o reaccional . Em seguida, o escopo da reacção foi explorado através da apresentação de fenilacetileno trifluoroborato para as condições optimizadas na presença de uma variedade de cloretos de acilo (Figura 2). Modesta a excelentes rendimentos podem ser obtidos, dependendo da natureza do substrato de cloreto de acilo. O âmbito de aplicação da reacção foi ainda avaliada através da preparação de vários exemplos adicionais de sais alkynyltrifluoroborate. A Figura 3 ilustra exemplos seleccionados de outros sais alkynyltrifluoroborate que podem ser empregues na preparação de ynones sob as condições desenvolvidas. Derivados de fenylacetylene electrões rolamento trifluoroborato substituintes doadores proporcionou os correspondentes produtos ynone em bons a excelentes rendimentos, enquanto derivados alifáticos de sais alkynyltrifluoroborate provou ser proporcionando rendimentos modestos ligeiramente menos reactivos. <img alt="Figura 1" src="/files/ftp_upload/52401/52401fig1highres.jpg" /> Figura 1: Preparação de Ynone 1a de fenilacetileno trifluoroborato S1 e cloreto de benzoílo Esquema que ilustra as condições para a preparação de ynone 1a incluindo a formação de dichloroborane intermediário reactivo.. <img alt="Figura 2" src="/files/ftp_upload/52401/52401fig2highres.jpg" /> Figura 2:. Representativas 1 H RMN espectro de ynone 1a Os desvios químicos e as integrações relativas dos protões característicos são rotulados. Figura 3:. Representativas 13 C, Espectro de RMN de ynone 1a desvios químicos dos carbonos característicos são rotulados. <img alt="Figura 4" src="/files/ftp_upload/52401/52401fig4highres.jpg" /> Figura 4:. HRMS espectro representativas de ynone 1a obtido através de ionização química à pressão atmosférica O valor m / z medido do [M + H] + ião é relatado. <img alt="Figura 5" src="/files/ftp_upload/52401/52401fig5highres.jpg" /> Figura 5: Reacções de sal phenylacetylenetrifluoroborate S1 com cloretos de ácido Estruturas e rendimentos para os produtos produzidos pela variação da identidade.do material de partida cloreto de acilo são ilustrados. As reacções foram corridas com 1 equivalente de cloreto de acilo, 1,5 equiv S1 phenylacetylenetrifluoroborate de potássio, e 1,5 equiv tricloreto de boro. <img alt="Figura 6" src="/files/ftp_upload/52401/52401fig6highres.jpg" /> Figura 6:. Reacções de vários alkynyltrifluoroborates com cloretos de acilo estruturas e os rendimentos para os produtos produzidos pela variação da identidade do material de partida alkynyltrifluoroborate são ilustrados. As reações foram executados com 1 equiv de cloreto de acila, 2,5 equiv sal de potássio organotrifluoroborate e 2,5 equiv tricloreto de boro. <table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> Entrada </td><td> Ácido de Lewis </td><td> Ácido de Lewis (equiv) </td><td> Condições </td><td> Rendimento (%) </td></tr><tr><td> 1 b &lt;/ Sup&gt; </td><td> SiO2 </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> traço </td></tr><tr><td> 3 </td><td> BF3 · OEt2 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> traço </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> traço </td></tr><tr><td> 9 </td><td> AlCl3 </td><td> 1 </td><td> tolueno </td><td> traço </td></tr><tr><td> 10 </td><td> AlCl3 </td><td> 2 </td><td> ClCH 2 CH 2 Cl </td><td> 33 </td></tr><tr><td> 11 </td><td> AlCl3 </td><td> 1 </td><td> DMSO </td><td> traço </td></tr><tr><td> 12 </td><td> AlCl3 </td><td> 2 </td><td> acetonitrila </td><td> traço </td></tr><tr><td> 13 </td><td> AlCl 3 .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> BBr3 </td><td> 1 </td><td> CH 2 Cl 2 </td><td> 20 </td></tr></tbody></table><strong&gt; Tabela 1:. Optimização de condições para a preparação de um ynone 1a Rendimento do produto 1a mediante variação das condições de reacção e do catalisador de ácido de Lewis. As reacções foram corridas um cloreto de benzoilo com 1 equiv e 1 equiv phenylacetylenetrifluoroborate potássio S1. B 1,5 equiv S1. C condições anidras. D A reacção foi realizada em material de vidro não-seco sob ar. E condições anidras + 1 ml de água.

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.

Síntese livre de metais de Ynones da Acil cloretos de potássio e sais Alkynyltrifluoroborate

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 visualizações.  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.

Vídeo: 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.

Preparação e Uso de Samário diiodeto (SMI<sub&gt; 2</sub&gt;) Em Organic Synthesis: The Role mecanístico de HMPA e (II) de Ni Sais na Reacção Barbier Samário

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

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.

Nucleosídeos Trisfosfatos - Da síntese à Caracterização 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 Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Síntese e caracterização de funcionalizados metal-organic frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the material with Au(III) ions. The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST), with several key modifications, including altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The resultant nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150&#160;nm. The nMST material was found to have a Brunauer-Emmett-Teller (BET) surface area of 285 m2g-1, which is more than an order of magnitude higher than the micron-sized MST. The isoelectric point of the nMST measured 3.34 pH units, which is a pH unit lower than that measured for the micron-size MST. The nMST material was found to serve as an effective ion exchanger under weakly acidic conditions for the preparation of an Au(III)-exchange nanotitanate. In addition, the formation of the corresponding peroxotitanate was demonstrated by reaction of the nMST with hydrogen peroxide.

The surfactant mediated sol-gel synthesis of nanosized monosodium titanate is described, along with preparation of the corresponding peroxide modified material. An ion-exchange reaction with Au(III) is also presented.

Síntese e Reacção Química de nanosize monossódico Titanate

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the ...

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.

Síntese e Caracterização de Supramoleculares Colloids

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.

Complexos de paládio N-heterocíclicos de carbeno: síntese a partir de sais de benzimidazólio e atividade catalítica em reações de formação de ligações carbono-carbono

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

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.

Reações Enzimáticas em Cascata para a Síntese de Aminoálcoois Quirais a partir 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.

Síntese de nanofios de Au substrato ligados através de um mecanismo de crescimento ativo de superfície

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.

Síntese e caracterização de nanopartículas de ouro Anfífilos

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.

Síntese de Oligosacárido de um pote programável e hierárquica

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