Enantiomeric Catalytic Formal Thiolation of 2,5-Dimethyl-3-[1-(arylsulfonyl)alkyl]pyrroles in an Oil/Water Biphasic System
The asymmetric synthesis of 3-sec-substituted pyrrole derivatives through vinylogous imine intermediates generated in situ from 2,5-dimethyl-3-[1-(arylsulfonyl)alkyl]pyrroles with high activity and enantioselectivity (up to 98 % ee) was examined. Employing a cinchona alkaloid based chiral bifunctional organocatalyst, the reaction of tritylthiol to sulfonylpyrroles delivered a series of highly enantioselective sulfur-containing 3-sec-substituted pyrroles.