Palladium-Catalyzed Selective [2 + 2 + 2] Annulation of 2-(2-Enynyl)pyridines with Arynes

J Org Chem. 2021 Sep 3;86(17):12403-12411. doi: 10.1021/acs.joc.1c01393. Epub 2021 Aug 11.

Abstract

The palladium-catalyzed chemo- and stereoselective [2 + 2 + 2] annulation reaction of 2-(2-enynyl)pyridines with arynes has been developed. A wide range of (E)- or (E/Z)-isomers of 2-(2-enynyl)pyridines and arynes was tolerated, providing a spectrum of (E)-phenanthrenylated 2-alkenylpyridines in good yield, together with the generation of a chiral axis between an alkene and a phenanthrene ring.