Asymmetric alpha-alkylation of N'-tert-butanesulfinyl amidines. Application to the total synthesis of (6R,7S)-7-amino-7,8-dihydro-alpha-bisabolene.

A highly diastereoselective alpha-alkylation of N'-tert-butanesulfinyl amidines has been developed along with methods for converting the alkylation products to enantiomerically enriched amines that incorporate both alpha- and beta-stereocenters. The utility of this chemistry is further demonstrated by the first asymmetric synthesis of the antimicrobial marine natural product (6R,7S)-7-amino-7,8-dihydro-alpha-bisabolene.