Remote Central-to-Axial Chirality Conversion: Direct Atroposelective Ester to Biaryl Transformation

Abstract

A strategy for the remote central-to-axial chirality conversion by simultaneous planarization of an encoding and a transient stereocenter is presented. Based on a diastereoselective double addition of a chiral 1,5-bifunctional organomagnesium alkoxide reagent to a broad range of aryl ester substrates, axially chiral biaryls are directly obtained upon in situ reduction. Various structurally distinct atropisomeric biaryl silanes that serve as valuable chiral biaryl anion surrogates are accessible in one step with e.r. values of up to 98:2.

Keywords: atropisomerism; biaryls; esters; organomagnesium reagents; stereoselectivity.