BINAPHANE-Catalyzed Asymmetric Synthesis of <i>trans</i>-β-Lactams from Disubstituted Ketenes and <i>N</i>-Tosyl Arylimines

Abstract

The development of a BINAPHANE-catalyzed formal [2 + 2]-cycloaddition of disubstituted ketenes and inexpensive <i>N</i>-tosyl arylimines that provides access to a variety of highly substituted β-lactams (16 examples) is described. The BINAPHANE catalytic system displays moderate to excellent enantioselectivity (up to 98% ee) and high diastereoselectivity in most cases, favoring formation of the <i>trans</i>-diastereomer (13 examples with dr ≥ 90:10)