Chemoselective Reduction of α-Cyano Carbonyl Compounds: Application to the Preparation of Heterocycles

beta-Aminoacrylates are reactive intermediates that are useful building blocks in synthesis. General methods for their preparation typically afford alpha and beta disubstitution patterns or beta only. Molecules with only alpha-substituents (beta-hydrogen) are much less well-known. A chemoselective reductive tautomerization of alpha-cyanoacetates, using DIBAL-H, has been developed to access these valuable synthons. alpha,beta-Unsaturated cyanoacetates and alpha-cyanoketones can, also, be selectively reduced via this methodology. A series of heterocycles were prepared using these beta-enamino carbonyl compounds.