Organocatalytic\nAsymmetric Electrophilic Amination\nof Allylic Boronates

The asymmetric addition of allylic\nboronates to electrophiles is\na powerful method for preparing chiral molecules bearing synthetically\nvaluable allylic moieties. While effective catalytic methods exist,\nthey have so far been limited to the enantioselective allyl- and crotyl-boration\nof carbonyl compounds and imines, thereby forming C–C bonds.\nHere, we present a strategy that expands the scope of this catalytic\nasymmetric platform to include the stereoselective formation of C–N\nbonds. We have identified an inexpensive and readily available chiral\ndiol that catalyzes the addition of allylic boronates to azodicarboxylates,\naffording chiral allylic hydrazides with high stereocontrol. This\nelectrophilic amination chemistry shows a broad substrate scope and\nrequires mild conditions, proceeding at ambient temperature. Mechanistic\nstudies reveal that the chiral diol catalyst facilitates the formation\nof a chiral allylic boronate through the reversible exchange of the\nboron’s achiral alkoxy ligand. By coordination with the electrophilic\nazodicarboxylate, the substrates mutually activate each other, allowing\nfor the stereoselective transfer of the allyl group.