Stereoselective Synthesis of Atropisomeric Bipyridine N,N′-Dioxides by Oxidative Coupling

Abstract

Bipyridine N,N′-dioxide is a structural fragment found in many bioactive compounds. Furthermore, chiral analogues secured their place as powerful Lewis base catalysts. The scope of the existing methods for the synthesis of atropisomeric bipyridine N,N′-dioxides is limited. Herein, we present a practical, highly chemo- and stereoselective method for oxidative dimerization of chiral pyridine N-oxides using O2 as a terminal oxidant. A series of 13 axially chiral bipyridine N,N′-dioxides were synthesized in up to 75% yield. © 2019 American Chemical Society.