A New Access to 4 <i>H</i>‐Quinolizines from 2‐Vinylpyridine and Alkynes Promoted by Rhodium–N‐Heterocyclic‐Carbene Catalysts

Abstract

Forging the lock that autolocks! Rh-NHC catalysts promote a new access to 4 H-quinolizine species from 2-vinylpyridine and terminal and internal alkynes through C-H activation and C-C coupling reactions (see figure). N-Bridgehead heterocycle formation is favored for internal- over terminal-substituted butadienylpyridine derivatives in a thermal 6π-electrocyclization process.