Formal [5+3] Cycloaddition of Zwitterionic Allylpalladium Intermediates with Azomethine Imines for Construction of N,O-Containing Eight-Membered Heterocycles

A formal [5+3] cycloaddition of zwitter-ionic allylpalladium intermediates with 1,3-dipoles is developed, providing N, O-containing eight-membered heterocyclic compounds in high yields. Catalytically generated zwitter-ionic allylpalladium intermediates in situ from vinylethylene carbonates or vinyloxiranes acted as dipolarophile.