Electro-Palladium-Catalyzed Asymmetric Allylic Benzylation with Electrophilic Benzylic Reagents

Asymmetric allylic benzylation reactions can be used to construct the backbone of chiral compounds via nucleophilic benzyl reagents but have yet to be achieved with benzylic electrophiles. In this report, an electroreductive Pd-catalyzed enantioselective allylic benzylation reaction was achieved with benzyl chloride via a radical trapping pathway. The diphosphine Pd complex works as both an electron transfer catalyst and a transition metal catalyst at different stages of the catalytic cycle. A weak hemilabile coordinative effect for the substrate was discovered, which could enhance the enantioselectivity up to 97% ee.