Development of Copper-Catalyzed Chemoselective Reactions.

Chemoselective reactions can contribute to streamlining synthesis of pharmaceuticals, agrochemicals, and other functional molecules by avoiding use of protecting groups. In this review, copper catalysts were demonstrated useful for developing two types of chemoselective reactions: C-C bond-forming reactions at an anomeric carbon of unprotected aldoses and difunctionalization reaction of C-C multiple bonds. The "soft" nucleophilic copper species exhibit orthogonal reactivity toward "hard" polar functional groups and preferentially react with "soft" functional groups. The catalysis also controls stereoselectivity and/or regioselectivity to provide value-added products from readily available feedstock compounds.