Ni-Catalyzed Synthesis of Fluoroarenes via [2+2+2] Cycloaddition Involving -Fluorine Elimination

A method for direct synthesis of tetrasubstituted fluoroarenes via nickel-catalyzed [2+2+2] cycloaddition is presented. The reaction combines one molecule of 1,1-difluoroethylene with two molecules of alkynes and involves sequential cleavage of the CF and CH bonds in difluoroethylene. The catalytic cycle is established by reduction of the intermediary Ni-II fluoride with a triethylborane-based borate.