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Why cyanide is used in benzoin condensation?

Why cyanide is used in benzoin condensation?

A cyanide ion usually catalyzes benzoin condensation. Cyanide is used because it is a good nucleophile, can stabilize the intermediate ion, and is an excellent leaving group.

Why did you use thiamine pyrophosphate as a catalyst instead of KCN in the benzoin condensation reaction?

The thiamine catalyst is the key: it allows the formation of what is essentially the equivalent of a nucleophilic benzaldehyde carbanion. The first step of the benzoin condensation is deprotonation of thiamine by hydroxide.

What is the role of thiamine hydrochloride in the synthesis of benzoin?

Thiamine is used as the catalyst for the benzoin condensation in Chem 30BL. The reaction of the thiamine hydrochloride with sodium hydroxide leads to the formation of the free thiamine. The color of the solution will change from colorless to dark yellow to pale yellow in the end.

What structural features do cyanide and thiamine have in common?

The structural features that cyanide and thiamine have in common is that they are both easily deprotonated which makes them both capable of catalyzing the benzoin condensation. Vitamin B1 (or thiamine) is “edible, nontoxic, and significantly greener than cyanide” (Kenneth et al., 2016).

What is the catalyst used in benzoin condensation?

A classic example is the benzoin condensation, first reported by Wöhler and Liebig in 1832 with a proposed mechanism in 1903 by Lapworth; cyanide is used as a catalyst to effect the dimerization of two benzaldehyde units [13].

Why is benzoin condensation important?

Benzoin condensation is an important carbon-carbon bond forming reaction. It is achieved by generating an acyl anion equivalent from one aldehyde molecule which adds to a second aldehyde molecule.

Why is thiamine pyrophosphate important?

Thiamine pyrophosphate (TPP), the active form of thiamine, functions as a coenzyme for a number of enzymes involved in carbohydrate metabolism, thus making metabolites from this metabolism and keto analogues from amino and fatty acid metabolism available for the production of energy.

Why is thiamine pyrophosphate important in a named enzyme reaction?

Thiamine pyrophosphate (TPP) acts as coenzyme for certain enzyme reactions in the metabolism of carbohydrate and amino acids, e.g. the decarboxylation of pyruvate to acetyl coenzyme A (CoA) via pyruvate dehydrogenase (providing the connection between the anaerobic glycolytic pathway and Kreb’s tricarboxylic acid cycle) …

Which solvent is used instead of cyanide in benzoin condensation?

thiamine pyrophosphate, can function in a manner completely analogous to cyanide ion in promoting reactions such as the benzoin condensation.

What are thiamine hydrochloride tablets for?

Thiamine (vitamin B1) is used to prevent or treat low levels of vitamin B1 in people who do not get enough of the vitamin from their diets. Most people who eat a normal diet do not need extra vitamin B1.

What role is thiamine playing in this reaction?

The main role of carbohydrates is to provide energy for the body, especially the brain and nervous system. Thiamin also plays a role in muscle contraction and conduction of nerve signals. Thiamin is essential for the metabolism of pyruvate, which is an important molecule in several chemical reactions in the body.

Why does cyanide ion behave as specific catalyst for benzoin condensation?

The cyanide ion helps the reaction to occur by acting as a nucleophile and facilitating the abstraction of protons, thus forming cyanohydrin. The cyanide ions serve as a catalyst in the reaction.