Enantioselective Synthesis of Axially Chiral Biaryl Sulfenamides via Addition–Elimination Strategy

Axially chirality is a crucial structural motif in natural products, pharmaceuticals, and chiral catalysts, making the development of efficient methods for constructing axially chiral compounds highly desirable. However, the enantioselective synthesis of axially chiral biaryl sulfenamides is a significant challenge for current chemical synthesis due to the lack of effective synthetic strategies. Herein, we report a novel addition-elimination strategy which involves copper/chiral cobalt anion-catalyzed sulfur-arylation and dealkylation of cyclic diaryliodoniums via a one-pot two-stepwise process for the construction of chiral biaryl sulfenamides. Various axial chiral biaryl sulfenamides were efficiently prepared in high yields (up to 95%) and enantioselectivities (up to 96% ee) which can be employed as novel organo-catalysts for the synthesis of epoxides and axially chiral hypervalent iodine catalysts for asymmetric catalysis, also they can be easily transformed into a wide range of valuable chiral biaryl sulfenamides and their derivatives with diverse functional groups. Moreover, control experiments demonstrated that this elimination process involved the sulfilimine as an intermediate, clarifying the reaction pathway. Finally, DFT calculation was carried out to systematically investigate the control of enantioselectivity, diastereoselectivity and chemoselectivity (C–S coupling or C–N coupling) of this protocol, providing a theoretical basis for the rational design of more efficient catalytic systems for axially chirality construction.