Catalytic asymmetric synthesis of sulfur-containing atropisomers by C-S bond formations

Chiral organosulfur compounds are not only widely distributed in bioactive natural products and pharmaceuticals, but also play a significant role in chiral ligands/catalysts. Throughout the history of synthetic organic chemistry, chemists have been absorbed in the construction of centrally chiral organosulfur compounds. Nevertheless, there are relatively few reports on installing sulfur functional groups into axially chiral compounds. Atropisomerism is one of the fundamental phenomena in nature, which ubiquitously exists in natural products. After more than a century of development, atropisomers have been designed and extensively applied to pharmaceuticals, functional materials and chiral ligands/catalysts. Due to the importance of chiral sulfur-containing atropisomers, there is an increasing demand for enantioselective synthesis of them. Recently, a diversity of approaches by C-S bond formations have been established for the construction of enantioenriched sulfur-containing atropisomers, however, there is no comprehensive review to summarize this great progress. In this mini-review, we summarize recent progress in catalytic asymmetric synthesis of sulfur-containing atropisomers by C-S bond formations, which includes sulfur nucleophilic reactions, sulfur electrophilic reactions and sulfur radical reactions. Furthermore, the reaction mechanisms are also discussed. We hope that this mini-review will enable more researchers to further explore this field.