Highly enantioselective monofluoromethylation of C2-arylindoles using FBSM under chiral phase-transfer catalysis.

The highly enantioselective addition of 1-fluoro-1,1-bis(phenylsulfonyl)methane (FBSM) to vinylogous imines generated in situ from 2-aryl-3-(1-arylsulfonylmethyl)indoles was achieved using chiral ammonium salts derived from cinchona alkaloids. One-pot conversion from 2-arylindoles with FBSM was also adaptable under the same reaction conditions. The key for this transformation is the effective use of the arylsulfonyl group.