Bölüm 15
α - Karbon Kimyası: Enoller, Enolatlar ve Enaminler
Enollerin reaktivitesi
Enols are a class of compounds where a hydroxyl group is attached to a carbon–carbon double bond, which implies that it is a vinyl alcohol. A ...
Enolat İyonlarının Reaktivitesi
Enolate ions are formed by the acid–base reaction of a carbonyl compound with a base. This leads to deprotonation of the α hydrogen atom, ...
Enol ve Enolat Çeşitleri
Aldehydes and ketones form enols, although only about 1% of the enol is present at the equilibrium for simple monocarbonyl compounds. The enol form is ...
Enolate Mekanizması Sözleşmeleri
When a carbonyl compound is treated with a strong base, the α position gets deprotonated to give a resonance-stabilized intermediate called an ...
Enolatların Bölgesel Seçici Oluşumu
As depicted in the figure below, the unsymmetrical ketones can form two possible enolates: less substituted or more substituted enolates. Usually, ...
Enolizasyonun Stereokimyasal Etkileri
The chiral α-carbon of the carbonyl compound is the stereocenter of the molecule. As shown in the figure below, when such a carbonyl compound ...
Aldehitlerin ve ketonların asit katalizli α-halojenasyonu
By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first ...
Aldehitlerin ve ketonların baz destekli α-halojenasyonu
α-Halogenation of aldehydes and ketones is a reaction involving the substitution of α hydrogens with halogens in the presence of a base. ...
Metil Ketonların Çoklu Halojenasyonu: Haloform Reaksiyonu
A method involving the transformation of methyl ketones to carboxylic acids using excess base and halogen is called the haloform reaction. It begins with ...
Karboksilik Asit Türevlerinin α-Halojenasyonu: Genel Bakış
Unlike aldehydes and ketones, carboxylic acids do not readily participate in α halogenation reactions via enols or enolate intermediates. However, ...
Karboksilik Asitlerin α-Bromlanması: Hell-Volhard-Zelinski Reaksiyonu
The method to achieve α-brominated carboxylic acids using a mixture of phosphorus tribromide and bromine is known as the ...
α-Halokarbonil Bileşiklerinin Reaksiyonları: Nükleofilik İkame
Nucleophilic substitution in α-halocarbonyl compounds can be achieved via an SN2 pathway. The reaction in α-haloketones is generally carried out ...
Enollerin Nitrozasyonu
The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in ...
C–C Bağ Oluşumu: Aldol Yoğunlaşmasına Genel Bakış
Aldol condensation is an important route in synthetic organic chemistry used to generate a new carbon–carbon bond under basic or acidic conditions. ...
Baz Katalizli Aldol İlave Reaksiyonu
As depicted in Figure 1, base-catalyzed aldol addition involves adding two carbonyl compounds in aqueous sodium hydroxide to form a β-hydroxy ...
Asit Katalizli Aldol İlave Reaksiyonu
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The ...
Aldollerin Enallere Dehidrasyonu: Baz Katalizli Aldol Yoğuşması
This lesson delves into the aldol condensation catalyzed by bases, where aldols undergo dehydration to enals. As shown in Figure 1, the β-hydroxy ...
Aldollerin Enonlara Dehidrasyonu: Asit Katalizli Aldol Yoğunlaşması
As shown in Figure 1, under acidic conditions, the β-hydroxy ketone undergoes dehydration via an E1 elimination reaction to form an enone.
Figure 1. ...
Molekül İçi Aldol Reaksiyonu
Intramolecular aldol reaction occurs in dicarbonyl compounds such as dialdehydes, diketones, and keto-aldehydes. The dicarbonyl compounds possess more ...
C–C Bağ Bölünmesi: Retro-Aldol Reaksiyonu
The reverse of the aldol addition reaction is called the retro-aldol reaction. Here, the carbon–carbon bond in the aldol product is cleaved under ...
Çapraz Aldol Reaksiyonları: Genel Bakış
Crossed aldol addition is the reaction between two different carbonyl compounds under acidic or basic conditions. Here, both the carbonyl compounds ...
Zayıf Bazlar Kullanılarak Çapraz Aldol Reaksiyonu
This lesson deals with the crossed aldol reaction using weak bases. The self-condensation of an aldehyde having α hydrogen is prevented by adding it ...
Enoleşemeyen Aromatik Aldehitler İçeren Ketonlar: Claisen-Schmidt Kondensasyonu
Benzaldehyde, like formaldehyde, lacks an α hydrogen and cannot enolize to form an enolate. Hence, the reaction of benzaldehyde with a ketone in the ...
Güçlü Bazlar Kullanılarak Çapraz Aldol Reaksiyonu: Yönlendirilmiş Aldol Reaksiyonu
The reaction between two different carbonyl compounds comprising α hydrogen in the presence of a strong base like lithium diisopropylamide (LDA) to ...
β-Diester ile Aldol Yoğuşması: Knoevenagel Yoğuşma
The Knoevenagel condensation is an aldol-type reaction involving the condensation of aldehydes or ketones with active methylene compounds such as ...
Esterlerden β-Ketoesterlere: Claisen Yoğuşmasına Genel Bakış
Regular Claisen condensation is a base-promoted reaction involving identical esters with two α hydrogens, condensing to produce β-ketoesters. It ...
Esterlerden β-Ketoesterlere: Claisen Yoğuşma Mekanizması
Regular Claisen condensation involves the synthesis of β-ketoesters by combining identical ester molecules bearing two α hydrogens in the ...
Aldol Yoğuşması ve Claisen Yoğuşması
Aldol condensation is an acid or base-catalyzed condensation between aldehydes or ketones to give an α,ꞵ-unsaturated carbonyl compound. A ...
Dikarboksilik Esterlerin Molekül İçi Claisen Yoğunlaşması: Dieckmann Siklizasyonu
Dieckmann cyclization is an intramolecular Claisen condensation of diesters. The reaction occurs in the presence of a base and generates a cyclic ...
Çapraz Claisen Kondensasyonları Yoluyla β-Dikarbonil Bileşikleri
Crossed Claisen condensations are base-promoted reactions between two different ester molecules producing β-dicarbonyl compounds. The reaction ...
α-Ketonların Enolat İyonları ile Alkilasyonu
Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by ...
Ketonların α-Alkilasyonunu Etkileyen Faktörler: Baz Seçimi
α-Alkylation of ketones is achieved in the presence of alkyl halides and a base. The reaction proceeds via the formation of an enolate ion followed ...
β-Ketoester Enolatlarının Alkilasyonu: Asetoasetik Ester Sentezi
Acetoacetic ester synthesis is a method to obtain ketones from alkyl halides and β-keto esters. The reaction occurs in the presence of an alkoxide ...
β-Diester Enolatlarının Alkilasyonu: Malonik Ester Sentezi
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
The ...
α.β-Doymamış Karbonil Bileşiklerine Konjuge Eklenmesi
α,β-Unsaturated carbonyl compounds are molecules bearing a carbonyl and alkene functionality in conjugation with each other. The conjugation in ...
Eşlenik Toplama (1,4-Toplama) ve Doğrudan Toplama (1,2-Toplama)
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic ...
Enolatların Eşlenik Eklenmesi: Michael Eklenmesi
The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition ...
Michael Eklenmesi ve Aldol Yoğunlaşması Yoluyla Sikloheksenonlar: Robinson Halkası
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, ...
α Sübstitüe Karbonil Bileşiklerinin Sentezi: Stork Enamin Reaksiyonu
α-Substituted ketones or aldehydes can be synthesized from enamines by the Stork enamine reaction, named after its pioneer Gilbert Stork. Enamines ...
Asitlere ve Alkollere Enolize Edilemeyen Aldehitler: Cannizzaro Reaksiyonu
The Cannizzaro reaction is a base-promoted redox reaction producing a primary alcohol and a carboxylic acid from two molecules of a nonenolizable ...
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