Phosphine‐Catalyzed Intermolecular Annulations of Fluorinated ortho‐Aminophenones with Alkynones – The Switchable [4+2] or [4+2]/[3+2] Cycloaddition

A phosphine‐catalyzed intermolecular annulation reaction of functionalized ortho‐aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2‐alkynylquinolines and benzo‐fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine.