Synthesis of Enantioenriched 2-Alkyl Piperidine Derivatives through Asymmetric Reduction of Pyridinium Salts

Org Lett. 2016 Oct 7;18(19):4920-4923. doi: 10.1021/acs.orglett.6b02401. Epub 2016 Sep 23.

Abstract

An Ir-catalyzed enantioselective hydrogenation of 2-alkyl-pyridines has been developed using ligand MeO-BoQPhos. High levels of enantioselectivities up to 93:7 er were obtained. The resulting enantioenriched piperidines can be readily converted into biologically interesting molecules such as the fused tricyclic structures 5, 6, and 7 in 99:1 er, providing a novel, concise synthetic route to this family of chiral piperidine-containing compounds.