Acyloin


Acyloins or α-hydroxy ketones are a class of organic compounds which all possess a hydroxy group adjacent to a ketone group. The named acyloin is derived from the fact that they are formally derived from reductive coupling of carboxylic acyl groups.

Synthesis

Classic organic reactions exist for the synthesis of acyloins.
s 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. 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.

Reactions