A Highly Stereoselective Addition of Lithiated Ynamides to Ellman–Davis Chiral <i>N‑tert</i>-Butanesulfinyl Imines

Abstract

A highly diastereoselective addition of lithiated ynamides to Ellman–Davis chiral imines is described. While additions of <i>N-</i>sulfonyl ynamides are highly stereoselective even without Lewis acids, the use of BF₃–OEt₂ completely reversed the stereoselectivity. In addition, oxazolidinone-substituted ynamides behaved differently and functioned better with BF₃–OEt₂, and the chirality of the oxazolidinone ring exerts no impact on the selectivity