Enantioselective Negishi Cross-Coupling of Secondary Benzylic Halides

Significance

Secondary benzylic halides can be efficiently reacted with primary alkylzinc bromides in the presence of chiral Ni-PyBox catalyst in DMA, giving the cross-coupling products in high yields and good enantioselectivities. Both enan­tiomers of a benzylic bromide can be converted into the same coupling product. 1-Chloroindanes are also suitable substrates for the reaction, although leading to lower yields of products. The reaction uses organozinc nucleophiles and therefore offers good functional group tolerance, including ketones, nitriles and phthalimide. This is one of the first reports of enantioselective alkyl-alkyl cross-coupling reactions.