One-Pot Domino Catalysis to Construct Alkyl/Aryl Pyrroles Initiated by Pd-TMM Annulation of Unactivated Imines

Org Lett. 2025 Jan 24;27(3):754-760. doi: 10.1021/acs.orglett.4c04281. Epub 2025 Jan 9.

Abstract

Herein, a one-pot domino catalyzed three-component process is described, which is initiated by a palladium/zinc cooperatively catalyzed cycloaddition between trimethylenemethane (TMM) and unactivated alkyl/aryl imines, followed by one-pot isomerization and Zn(OTf)2-catalyzed DDQ oxidation, furnishing valuable substituted pyrroles. We disclose that the palladium/zinc cooperative catalysis affords a dual-Zn(OTf)2-stabilized azapalladacycle, wherein the Pd-N bond is polarized by Zn(OTf)2, facilitating a unique outer-sphere allylic amination. Moreover, subsequent DDQ dehydrogenation can be feasibly promoted by zinc catalysis.