B(C₆F₅)₃-Catalysed Alkylation of Imidazo[1,2-a]pyridines Using ,-Unsaturated Ketones

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 alpha,beta-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.