Diastereoselective addition of chlorotitanium enolate of N-acyl thiazolidinethione to O-methyl oximes: a novel,stereoselective synthesis of alpha,beta-disubstituted beta-amino carbonyl compounds via chiral auxiliary mediated azetine formation

We have discovered a novel and highly diastereoselective synthesis of azetinyl thiazolidine-2-thiones that utilizes additions of the chlorotitanium enolates of N-acyl thiazolidin-2-thiones to O-methyl aldoximes. The "anti" azetines can be subsequently converted to the corresponding alpha,beta-disubstituted beta-amino carbonyl compound with retention of stereochemistry. The formation of azetine and the product of its "hydrolytic" opening has been confirmed by X-ray crystallographic analyses.