Nickel-Catalyzed Unsymmetrical Bis-Allylation of Alkynes

Angew Chem Int Ed Engl. 2023 Apr 17;62(17):e202300036. doi: 10.1002/anie.202300036. Epub 2023 Mar 15.

Abstract

The catalytic bis-allylation of alkynes is an important but challenging protocol to construct all-carbon tetra-substituted alkenes. Particularly, the catalytic unsymmetrical bis-allylation of alkynes remains as an underexplored task to date. We herein report an unprecedented unsymmetrical bis-allylation by simultaneously utilizing electrophilic trifluoromethyl alkene and nucleophilic allylboronate as the allylic reagents. With the aid of robust Ni0 /NHC catalysis, valuable skipped trienes can be obtained in high regio- and stereo-selectivities under mild conditions. Mechanistic studies indicate that the reaction may proceed through a β-fluorine elimination of a nickelacycle followed by a transmetalation step with allylboronate. The present method exhibits a good tolerance of various functional groups. Besides, the skipped triene products can undergo an array of elaborate transformations, which highlights the potential applications of this strategy.

Keywords: Alkyne; Gem-Difluoroalkene; Nickel Catalysis; Skipped Triene; Unsymmetrical Bis-Allylation.