Enantioselective Synthesis of Planar‐Chiral Sulfur‐Containing Cyclophanes by Chiral Sulfide Catalyzed Electrophilic Sulfenylation of Arenes

Abstract

An efficient catalytic asymmetric electrophilic sulfenylation reaction for the synthesis of planar‐chiral sulfur‐containing cyclophanes has been developed for the first time. This was achieved by using a new Lewis base catalyst and a new ortho‐trifluoromethyl‐substituted sulfenylating reagent. Using the substrates with low rotational energy barrier, the transformation proceeded through a dynamic kinetic resolution, and the high rotational energy barrier of the substrates allowed the reaction to undergo a kinetic resolution process. Meanwhile, this transformation was compatible with a desymmetrization process when the symmetric substrates were used. Various planar‐chiral sulfur‐containing cyclophanes were readily obtained in moderate to excellent yields with moderate to excellent enantioselectivities (up to 97% yield and 95% ee). This approach was used to synthesize pharmaceutically relevant planar‐chiral sulfur‐containing molecules. Density functional theory calculations showed that π–π interactions between the sulfenyl group and the aromatic ring in the substrate play a crucial role in enantioinduction in this sulfenylation reaction.