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

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