Catalytic Carbon-Carbon Bond-Forming Reactions of Weakly Acidic Carbon Pronucleophiles Using Strong Brønsted Bases as Catalysts.

Catalytic carbon-carbon bond-forming reactions of weakly acidic carbon pronucleophiles with N-aryl imines, α,β-unsaturated amides, and others under proton-transfer conditions were developed by designing strongly basic reaction intermediates known as product bases. The reactions proceed smoothly in the presence of a catalytic amount of strong base such as KH or alkaline metal amides. Modification of the metal cations by using chiral macrocyclic crown ethers allowed catalytic asymmetric 1,4-addition reactions to proceed with high enantioselectivities. This concept can be applied to Brønsted-base-catalyzed reactions of a wide range of weakly acidic carbon pronucleophiles.