Acyloin

In chemistry acyloins are a class of organic compounds which all possess the secondary alpha-hydroxy ketone functional group. Thus, they all contain a hydroxyl group placed on the α-position of a carbonyl group. The named acyloin is derived from the fact that they are formally derived from reductive coupling of carboxylic acyl groups.

Classic organic reactions exist for the synthesis of acyloins.

Enolates can be oxidized by sulfonyloxaziridines. The enolate reacts by nucleophilic displacement at the electron deficient oxygen of the oxaziridine ring.

This reaction type is extended to asymmetric synthesis by the use of chiral oxaziridines derived from camphor (camphorsulfonyl oxaziridine). Each isomer gives exclusive access to one of the two possible enantiomers. This modification is applied in the Holton taxol total synthesis.

In the enolate oxidation of the cyclopentaenone below with either camphor enantiomer, the trans isomer is obtained because access for the hydroxyl group in the cis position is limited. The use of the standard oxaziridine did not result in an acyloin.

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