Fluorinated triarylboranes are employed as a metal free and sustainable catalysts for alkylation of 2-phenylimidazo[1,2-a]pyridines with α,β-unsaturated ketones.

Abstract

Fluorinated triarylboranes have shown a breadth of reactivity as catalysts for organic transformations, particularly in carbon-carbon bond forming reactions. Herein we report a facile, metal-free synthetic route for the addition of 2-phenylimidazo[1,2-a]pyridines to α,β-unsaturated ketones using B(C₆F₅)₃ as a metal-free catalyst. 25 examples of reactions leading to products in up to 97 % yield are reported. DFT studies show the role of B(C₆F₅)₃ and hydrogen shuttling in the mechanism of this Michael alkylation.