A NOVEL AND USEFUL SYNTHETIC WAY TO CHIRAL α-SULFINYL CYCLIC KETONES BY THE ACID-CATALYZED REACTION OF ENOL SILYL ETHERS OF CYCLIC KETONES WITH CHIRAL SULFINATES

The acid-catalyzed reactions of enol silyl ethers of cyclic ketones with chiral sulfinic esters provided a new and general entry to optically active α-sulfinyl ketones. Reaction of the enol silyl ether of cyclohexanone with methyl (S)-p-toluenesulfinate in the presence of boron trifluoride etherate (2.0 equiv.) produced (Rs)-2-p-toluenesulfinylcyclohexanone with inversion of configuration in 98.3% stereospecificity at the sulfur atom. This method was applicable smoothly to enol silyl ethers of other cyclic ketones with high stereospecificity.