Stereoselective monofluoromethylation of N-tert-butylsulfinyl ketimines using pregenerated fluoro(phenylsulfonyl)methyl anion.

Pregeneration of fluoro(phenylsulfonyl)methyl anion (PhSO(2)CHF(-)) paves the way for the efficient and highly stereoselective monofluoromethylation of (R)-N-tert-butylsulfinyl ketimines. The stereocontrol mode of the present diastereoselective monofluoromethylation of ketimines is different from the previously known nucleophilic fluoroalkylation of (R)-N-tert-butylsulfinyl aldimines, which suggests that a cyclic six-membered transition state (rather than a nonchelation controlled one) is involved in the current ketimine reaction.