2
$\begingroup$

Apparently carboxylic acid derivatives such as cyanohydrins can be taken back to "daddy" - a carboxylic acid - under the right conditions. This involves acid, water, and "high heat." What, however, is the mechanism of a cyanohydrin going back to daddy?

$\endgroup$
  • 3
    $\begingroup$ Cyanohydrins are typically formed from aldehydes and ketones and can be hydrolyzed to alpha-hydroxy carboxylic acids. Is it the mechanism of formation of the alpha-hydroxy carboxylic acid that you are asking about? $\endgroup$ – ron Oct 20 '14 at 15:47
  • $\begingroup$ Yes I believe so $\endgroup$ – Dissenter Oct 20 '14 at 15:49
6
$\begingroup$

In the cyanohydrin reaction aldehydes or ketones can react with HCN to form a cyanohydrin. Inorganic cynanides and acid can be used in place of HCN, to generate the required cyanide anion. The reaction proceeds by typical addition of the nucleophilic cyanide anion to the carbonyl carbon to form the tetrahedral intermediate, which can ultimately be protonated to yield the corresponding cyanohydrin.

enter image description here

Once formed, the nitrile group of the cyanohydrin can undergo acidic (or basic) hydrolysis by the same mechanism as any other common nitrile. The only difference in the case of a cyanohydrin is that the "R" group contains a hydroxyl substituent on its alpha carbon.

enter image description here

A useful variant of cyanohydrin formation is the Strecker amino acid synthesis. Instead of forming a cyanohydrin, an aminonitrile is formed and the nitrile is hydrolyzed to the corresponding alpha-amino acid. A detailed mechanism can be found in the above link.

enter image description here

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.