Imidazolethiones: novel and efficient organocatalysts for asymmetric Friedel-Crafts alkylation

Imidazolethiones organocatalyzed the asymmetric Friedel-Crafts alkylation of pyrroles with alpha,beta-unsaturated aldehydes was achieved to afford the corresponding adducts in moderate to good yields and good to excellent enantioselectivities. The possible mechanism was proposed. (C) 2010 Elsevier Ltd. All rights reserved.