A Concise Enantioselective Synthesis of Fluorinated Pyrazolo-Piperidine GSK3901383A Enabled by an Organocatalytic Aza-Michael Addition

Org Lett. 2024 Mar 1;26(8):1533-1538. doi: 10.1021/acs.orglett.3c03694. Epub 2024 Feb 16.

Abstract

A highly enantioselective organocatalytic aza-Michael addition of 4-nitro-pyrazole to ethyl (E)-2,2-difluoro-5-oxopent-3-enoate has been developed. This reaction enabled a concise, four-step, stereoselective synthesis of highly functionalized 3,3-difluoro-4-pyrazolo-piperidine GSK3901383A, a key intermediate for the synthesis of a leucine-rich repeat kinase 2 inhibitor API. Computational analysis provided insight into the steric requirements of the catalytic system, enabling rational selection of a highly selective catalyst.