Synergistic Effects of Boron and Oxygen Interaction Enabling Nickel-Catalyzed Exogenous Base-Free Stereoselective Arylvinylation of Alkynes through Vinyl Transposition

초록

While organoboron compound is one of the most attractive and widely used nucleophiles in transition-metal-catalyzed coupling processes, they require sacrificial reagents for transmetalation (TM) processes. Herein, we report an unprecedented exogenous base-free procedure of a stereoselective Ni-catalyzed arylvinylation of alkynes. It was revealed that Ni(0) species generated in situ from an air-stable Ni(II) precursor by a P^N ligand undergoes oxidative cyclization with an unactivated enyne to afford a nickellacycle intermediate, where a B-assisted C-O bond cleavage results in the formation of a TM-active boronate complex affording tetrasubstituted 1,3-diene products stereoselectively. A series of controlled experiments and density functional studies have been carried out to support the mechanistic proposal. The highly functionalized product comprising the stereoselective 1,3-diene system shows potential as an important building block in the synthesis of complex organic architectures. © 2021 American Chemical Society. All rights reserved.

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