Catalytically atroposelective ring-opening of configurationally labile compounds to access axially chiral biaryls

Abstract

Axially chiral biaryl scaffolds are vital in natural products, pharmaceuticals, and asymmetric synthesis. Catalytically atroposelective ring-opening of configurationally labile compounds, pioneered by Bringmann, has received continuous attention in the past few years, becoming one of the most unique and powerful strategies to construct axially chiral biaryls. Biaryl lactones and lactams, cyclic diaryliodonium salts, dinaphthothiophenes, diarylsulfonium salts, diarylfurans, five-membered silafluorenes and 9-aryl-9H-fluoren-9-ols are identified as representative successful skeletons. These configurationally labile compounds feature a strained cyclic structure which significantly improved their reactivity in catalytic transformations compared to the corresponding non-cyclic structures. In this minireview, we evaluate and summarize the progress in this field, and briefly state our personal perspectives on the future advancement of this direction.