Developing Biarylhemiboronic Esters for Biaryl Atropisomer Synthesis via Dynamic Kinetic Atroposelective Suzuki-Miyaura Cross-Coupling.

We herein introduce biarylhemiboronic esters as a new type of bridged biaryl reagent for asymmetric synthesis of axially chiral biaryl structures, and the palladium-catalyzed asymmetric Suzuki-Miyaura cross-coupling of biarylhemiboronic esters is developed. This dynamic kinetic atroposelective coupling reaction exhibits high enantioselectivity, good functional group tolerance, and a broad substrate scope. The synthetic application of the current method was demonstrated by transformations of the product and a programmed synthesis of chiral polyarene. Preliminary mechanistic studies suggested that the reaction proceeded via an enantio-determining dynamic kinetic atroposelective transmetalation step.