Synthesis of Atropisomeric Triazoles with Vicinal 1,5-Diaxes via Rhodium-Catalyzed Click Chemistry

Axially chiral scaffolds, namely atropisomers, are widely found in natural products, pharmaceuticals, functional materials as well as chiral catalysts and ligands. Over the past decades, the construction of axial chirality has become one of hot topics in organic chemistry, and remarkable advances have been achieved. However, these studies mainly focus on the preparation of atropisomers with a single axis, while the synthesis of atropisomers with more than one axes remains elusive, probably owing to the formidable challenges in establishing multi-axes with high chiral control. Herein we report a practical and modular platform technology of click chemistry for the construction of biaxial atropisomers. In this protocol, a wide range of readily available internal alkynes and azides could rapidly assemble to a variety of atropisomeric triazoles with vicinal 1,5-C−N/C−C-diaxes through Rh-catalysis in excellent yields with high regioselectivities, diastereoselectivities and enantioselectivities. This click technology features broad substrate scope, very mild reaction conditions, high efficiency and scalability, demonstrating tremendous potential in chemistry and biology.