Frustrated Lewis pair-catalyzed double hydroarylation of alkynes with N-substituted pyrroles

Abstract

Metal-free hydroarylation of alkynes with N-substituted pyrroles is shown to be most efficiently mediated by B(C₆F₅)₃ to yield 12 variants of dipyrrole-alkanes, a mono-hydroarylation product and a tetrahydroarylation product of a bis-alkyne. These products were generally obtained in good to excellent yields (up to 95%). Control experiments suggest a mechanism involving FLP addition of the borane and pyrrole to alkyne.