Development and Cycloaddition Reactivity of a New Class of Pyridine-Based Mesoionic 1,3-Dipole.

We describe here the development and structural characterization of a new type of mesoionic 1,3-dipole, which can be generated in the one-step reaction of imines with pyridine- or quinoline-based acid chlorides. Coupling the formation of these dipoles with alkyne cycloaddition can open a general and modular route to synthesize indolizines from combinations of available and diversifiable building blocks.