Highly regio- and stereoselective asymmetric bromoazidation of chiral alpha,beta-unsaturated carboxylic acid derivatives: scope and limitations

Saumen Hajra; Manishabrata Bhowmick; Debarshi Sinha

doi:10.1021/jo061593k

Highly regio- and stereoselective asymmetric bromoazidation of chiral alpha,beta-unsaturated carboxylic acid derivatives: scope and limitations

J Org Chem. 2006 Nov 24;71(24):9237-40. doi: 10.1021/jo061593k.

Authors

Saumen Hajra¹, Manishabrata Bhowmick, Debarshi Sinha

Affiliation

¹ Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India. shajra@chem.iitkgp.ernet.in

PMID: 17109556
DOI: 10.1021/jo061593k

Abstract

Lewis acid catalyzed asymmetric bromoazidation of chiral alpha,beta-unsaturated carboxylic acid derivatives was performed using N-bromosuccinimide (NBS) and trimethylsilyl azide (TMSN3) 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.