Structure Guided Design of VANOL-Imidodiphosphorimidate Catalysts for the Catalytic Enantioselective Bromospiroketalization Reaction

This report presents a structure-guided approach for the optimization of VANOL-derived imidodiphosphorimidates as catalysts for the halonium-ion-induced spiroketalization reaction. Fine tuning of the catalyst active site, alongside enhanced acidity, was required to achieve high catalytic activity for the spiroketalization reaction. A wide range of substrates was well tolerated yielding halogenated spiroketals in high yields, diastereoselectivities, and enantioselectivities.