Practical Large-Scale Synthesis of 3,4-Isopropylidenedioxypyrrolidine Hydrotosylate: Atom Economical Self-Hydrogenolysis of a Crystalline Borane-Benzylamine Adduct
An efficient four-step sequence has been developed for thesynthesis of 3,4-isopropylidenedioxypyrrolidine hydrotosylatestarting from inexpensive N-benzylmaleimide. This approachfeatures a novel N-debenzylation procedure that utilizes thecorresponding borane-benzylamine complex as an internalhydrogen-transfer source. This palladium-catalyzed tandemprotonolysis/hydrogenolysis allows cleavage of the borane-amine adduct and debenzylation in a single operation.