Controllable O-Nucleometalation Cyclization Strategy: Access to Divergent Ring-Functionalized Molecules

The vinyl moiety-assisted selective O-nucleopalladation is reported, which offers rapid constructions of cycloolefins and cyclopropanes via oxidant-induced cyclization of enynes. O-2 resulted in the unexpected 6-endo-Heck cyclization, while CuCl2 led to a 5-exo-trig pathway and synergetic S(N)2-type C-C bond formation. Amide works as an O-transferred nucleophilic group to activate the alkyne moiety, which induced divergent annulation processes. Moreover, the regenerated amides could be used for further modifications.