Pd-catalyzed electrophilic cyclization/C–H annulation cascade of 1,8-diyne oxime ethers to access fused oxepines

Abstract

Harnessing the metal-catalyzed cascade cyclizations constitutes a challenging task but offers an outstanding tool to access polycyclic scaffolds. We present herein a Pd(II)-catalyzed cascade cyclization of 1,8-diyne oxime ethers via a consecutive intramolecular oxy-palladation/carbopalladation/C–H annulation for the construction of oxepine-fused trinuclear polycyclic scaffolds. Some control and kinetic experiments were carried out to understand the mechanism, and a few product elaborations were achieved to further showcase the potential of the reaction.