Enantioselective synthesis of chiral 2,2,2-trifluoroethyl lactams via asymmetric hydrogenation

Abstract

Enantioselective hydrogenation of α-trifluoromethylidene lactams catalyzed by the Rh/f-spiroPhos complex has been first developed. The method provides an efficient and highly enantioselective approach for the synthesis of a variety of chiral 2,2,2-trifluoroethyl lactams with excellent enantioselectivities (up to 99.9% ee) and high turnover numbers (TON of up to 10 500). Moreover, the obtained hydrogenation products were also successfully transformed into chiral 2,2,2-trifluoroethyl pyrrolidine, 2-piperidone, and an inhibitor of the donor receptor tyrosine kinase effector Raf.