One-Pot Domino\nCatalysis to Construct Alkyl/Aryl Pyrroles\nInitiated by Pd-TMM Annulation of Unactivated Imines

Herein, a one-pot domino catalyzed three-component process\nis described,\nwhich is initiated by a palladium/zinc cooperatively catalyzed cycloaddition\nbetween trimethylenemethane (TMM) and unactivated alkyl/aryl imines,\nfollowed by one-pot isomerization and Zn(OTf)<sub>2</sub>-catalyzed\nDDQ oxidation, furnishing valuable substituted pyrroles. We disclose\nthat the palladium/zinc cooperative catalysis affords a dual-Zn(OTf)<sub>2</sub>-stabilized azapalladacycle, wherein the Pd–N bond\nis polarized by Zn(OTf)<sub>2</sub>, facilitating a unique outer-sphere\nallylic amination. Moreover, subsequent DDQ dehydrogenation can be\nfeasibly promoted by zinc catalysis.