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I know the Cannizzaro reaction takes place in carboxyl compounds without $\alpha$-H with the regular examples being formaldehyde and benzaldehyde.

But can this reaction take place with say diphenylmethanone or di ter-butyl ketone (2,2,4,4-tetramethylpentan-3-one) or 2,2-dimethylpropanal ?

I couldn't find any examples of these compounds showing the cannizzaro reaction.

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  • $\begingroup$ Possible typo : "carboxyl compounds without $\ce{\alpha-H}$..." . It should have been "carbonyl compounds without..." $\endgroup$ – Shoubhik Raj Maiti Nov 26 '17 at 11:37
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As far as I'm aware, the Cannizzaro reaction can't occur with ketones, only aldehydes. The reaction mechanism involves the transfer of hydride from the former carbonyl carbon (of the tetrahedral intermediate resulting from hydroxide's nucleophilic addition to the carbonyl carbon), during which step the carbonyl reforms, yielding a carboxylic acid. Since a ketone, by definition, has no hydrogens bonded to the carbonyl carbon, it obviously can't undergo such a reaction. I would expect ketones with no $\alpha$-hydrogens to be essentially unreactive with hydroxide, since aldol reactions and keto-enol tautomerism are impossible with no $\alpha$-hydrogens, and most hydrates are unstable.

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  • $\begingroup$ Means cross cannizzaro can be possible between any aldehyde + ketone mixture and we will get only single product as aldehyde get oxidised and ketone get reduced? Is it correct? $\endgroup$ – Mohit Feb 13 at 13:03
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As Greg E. wrote in his answer, Cannizzaro reaction does not usually occur with ketones. However there are some instances where ketones give Cannizzarro products. From the Wikipedia page of Cannizarro reaction:

Certain ketones can undergo a Cannizzaro-type reaction, transferring one of their two carbon groups rather than the hydride that would be present on an aldehyde.

The paper [1] gives an instance of such reaction. A reaction from the paper is:first step Here, the 3 H-atoms of the methyl group of acetophenone(1-Phenylethan-1-one) are replaced by F-atoms. Therefore, it is a ketone without any $\ce{\alpha-H}$. After nucleophilic attack by $\ce{OH^-}$ on the carbonyl carbon, the intermediate expels a trifluoromethyl carbanion, and forms a carboxyllic acid. enter image description here In the next step, the carbanion attacks another ketone molecule to form alcohol. However, according to the paper these products are formed only when solid NaOH with DMF as solvent, is used. Hydrated form of the ketone (gem-diol) also exists in a significant amount in the product mixture.

References:

  1. Jiang, X.; Matsukawa, S.; Kakuda, K.; Fukuzaki, Y.; Zhao, W.; Li, L.; Shen, H.; Kojima, S.; Yamamoto, Y. Efficient synthesis of tetradecafluoro-4-phenylheptan-4-ol by a Cannizzaro-type reaction and application of the alcohol as a bulky Martin ligand variant for a new anti-apicophilic phosphorane. Dalton Trans. 2010, 39 (41), 9823. DOI: 10.1039/C0DT00539H.
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  • $\begingroup$ Means cross cannizzaro can be possible between any aldehyde + ketone mixture and we will get only single product as aldehyde get oxidised and ketone get reduced? Is it correct? $\endgroup$ – Mohit Feb 13 at 13:04
  • $\begingroup$ @Mohit To be fair, I don't know the answer to the question. But if I had to guess, I would say that yes, the aldehyde should get oxidised and the ketone reduced. I will check some books and try to come up with an answer. $\endgroup$ – Shoubhik Raj Maiti Feb 14 at 21:03
  • $\begingroup$ @Mohit, Also note that cannizaro type reaction that I have wrote in the answer does not happen with any ketone, only specific ketones that can expel relatively stable carbanions. $\endgroup$ – Shoubhik Raj Maiti Feb 14 at 21:05

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