Divergent and Regioselective Synthesis of Pyrazolo[1,5- a]pyridines and Imidazo[1,5- a]pyridines

Org Lett. 2021 Jun 18;23(12):4694-4698. doi: 10.1021/acs.orglett.1c01431. Epub 2021 May 26.

Abstract

Nitrogenous heterocycles are ubiquitous in pharmaceuticals and drug-like compounds; however, regioselective synthesis has proved challenging. Herein we report our efforts to develop a regioselective method for the synthesis of pyrazolo[1,5-a]pyridines and the serendipitous discovery of a protocol for the regioselective formation of imidazo[1,5-a]pyridines. Together, these transformations allow for the rapid and selective formation of two important heterocyclic motifs from a common intermediate.