“…Catalytic generation of zwitterion/dipole intermediates and further cyclization with different acceptors proves to be one of the most powerful strategies in this event. , Specifically, transition metal catalyzed decarboxylative reactions for this purpose have attracted much research interest and advanced remarkably as a result of their advantages of easy operations, redox neutrality, and only CO 2 -byproduct generation . In this sense, previous work on the Pd-catalyzed decarboxylation of vinyl carbonate A /carbamate B gained great success in preparation of a huge range of useful and otherwise synthetically challenging O - or N -heterocycles (Scheme a). − Vinyl benzoxazinanones also showed excellent reactivity under transition metal catalysis resulting in tetrahydroquinolines (Scheme b) . The key to success of these transformations is the in situ generation of zwitterionic π-allyl-Pd intermediate t1 or t2 from the cyclic vinyl carbonate/carbamate precursors upon CO 2 extrusion (Scheme a,b). ,, Thus, to design reactive precursors toward the formation of novel zwitterionic intermediates is essential for the efficient and diverse construction of interesting and valuable cyclic structures.…”