Catalytic enantioselective synthesis of chiral tetraarylmethanes

While synthetic chemistry has experienced substantial development in the past century, challenges still remain to fully satisfy the needs in drug development. A bias in sampling linear and disc-shaped molecules in drug discovery over spherical ones has existed due to the lack of efficient access to the latter chemical space. Specifically, efficient strategies to synthesize tetraarylmethanes, a unique family of spherical molecules, has remained scarce. In particular, there has been essentially no efficient asymmetric synthesis of chiral tetraarylmethanes due to the overwhelming steric congestion and challenging stereocontrol encountered in assembly of the all-aryl-substituted quaternary stereocentre. Here we disclose an efficient catalytic synthesis of chiral tetraarylmethanes with high enantioselectivity via a stereoconvergent formal nucleophilic substitution reaction. Control experiments and density functional theory calculations provided strong support on hydrogen bonding interactions as the key elements to successful stereocontrol. The obtained enantioenriched products showed impressive preliminary anticancer activities.