Facile access to chiral 1-pyrrolines through Rh-catalyzed enantioselective partial hydrogenation of unprotected simple pyrroles

Highly enantioselective Rh-catalyzed partial hydrogenation of unprotected simple 2-alkyl-5-aryldisubstituted pyrroles has been successfully developed, generating a series of chiral 1-pyrroline derivatives generally with excellent results (95%-99% yields, 91%-96% ee). Moreover, 2,5-aryl-1H-pyrroles were hydrogenated well in high yields and good enantioselectivities. This efficient protocol features easily accessible substrates, wide substrate scope, well functional group compatibility, commercially available rhodium precursor and chiral ligand. It provides a versatile route to access chiral 1-pyrroline derivatives that are of great importance in organic synthesis and pharmaceutical chemistry. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.