Highly regio- and stereoselective asymmetric bromoazidation of chiral α,β-unsaturated carboxylic acid derivatives: Scope and limitations

Article abstract of DOI:10.1021/jo061593k

(Chemical Equation Presented) Lewis acid catalyzed asymmetric bromoazidation of chiral α,β-unsaturated carboxylic acid derivatives was performed using N-bromosuccinimide (NBS) and trimethylsilyl azide (TMSN ₃) as the bromine and azide sources. Among the Lewis acids, Yb(OTf)₃ was found to be the best catalyst. Regio- and anti-selectivity of 100% and moderate to good diastereoselectivity (up to 89:11) with good yields were obtained when Oppolzer's bornane sultam chiral auxilairy was used. Diastereoselectivity of > 95:05 was observed when (2S,5S)-2,5-diphenylpyrrolidine was used as the chiral auxiliary.