Phosphine-catalyzed [5+1] annulation of β′-acetoxy allenoates: straightforward access to tetrahydroquinoline derivatives

Abstract

An unprecedented phosphine-catalyzed [5+1] annulation of β′-acetoxy allenoates with 1,5-dinucleophiles has been developed, which provides novel and facile access to functionalized tetrahydroquinolines in good to high yields in the presence of PPh₃ and K₃PO₄ under mild reaction conditions. Notably, it is the first report of β′-acetoxy allenoates acting as C1 synthons in Lewis base-catalyzed annulation reactions.