Tunable mono- or 1,1-double Heck-type coupling reaction of unconjugated amido-alkenes with remote benzylic C(sp3)–H of N-fluorobenzamides†

Abstract

This work described a tunable copper-catalyzed intermolecular oxidative functionalization reaction of unconjugated amido-alkenes directed by the remote benzylic free radical of N-fluoroamides, and the corresponding monoalkylation and 1,1-bialkylation products of unconjugated amido-alkenes were obtained in good yields, respectively. These two reactions proceeded via a nitrogen-centered free radical generation of N-fluoroamide in the presence of a copper salt, an intramolecular 1,5-hydrogen atom transfer, followed by the newly formed benzylic free radical addition to the alkenes, single-electron transfer, and β-hydride elimination multi-step sequential process, as represented by a mono-Heck-type coupling and a 1,1-double Heck-type coupling reaction of unactivated alkenes on the whole. These protocols showed good substrate scope and produced polysubstituted alkenes, which could be further transformed into diverse structural molecules. Besides, the plausible reaction mechanism was proposed using a combination of density functional theory calculations and control experiments.