Enantioselective 1,4-Michael addition reaction of pyrazolin-5-one derivatives with 2-enoylpyridines catalyzed by Cinchona derived squaramides

Abstract

The bifunctional nature of the cinchonidine squaramides has been successfully employed to catalyze the enantioselective 1,4-Michael addition reaction of pyrazolin-5-ones with 2-enoylpyridines under mild reaction conditions. Through this methodology, a broad range of optically active heterocyclic derivatives bearing both pyrazole and pyridine motifs have been synthesized in yields up to 88% and enantiomeric excess up to 96%.