Simultaneous Construction of Axial and Central Stereogenicity by Cobalt-Catalyzed Stereoconvergent Reductive Coupling of Heterobiaryl Triflates and Aldehydes.

Abstract

Catalytic stereoconvergent coupling of racemic heterobiaryl triflates and aldehydes promoted by a readily available chiral cobalt complex is presented. Such processes represent an unprecedented reaction pathway for cobalt catalysis that enable simultaneous construction of axial and central stereogenicity through diastereo- and enantioselective dynamic kinetic transformations and introduction of a chiral fragment onto the heterobiaryl cores without the requirement of preforming stoichiometric amounts of organometallic reagents, affording densely functionalized secondary alcohols in up to 96% yield, >98:2 dr and >99.5:0.5 er. Preliminary investigations on the application of the products demonstrate their potential for serving as a new class of chiral catalysts and ligands. Mechanistic studies suggest that a dynamic kinetic stereoselective process induced by chiral cobalt catalysis is involved.