Cu/Pd-cocatalyzed cascade asymmetric alkene boration and Z-retentive allylic substitution reactions are described. Taking advantage of palladium catalysts that well tune the rates of both the π-σ-π isomerization process of the π-allyl-palladium species and nucleophilic substitution, either Z-retentive or Z-to-E allylic substitution reactions can be achieved, with alkyl copper nucleophiles generated in situ via Cu-catalyzed alkene boration. Chiral Z- and E-olefins containing an organoboronate functional group are afforded under Cu/Pd relay catalysis from the same starting materials. Both reactions proceed with high yields (up to 95%), excellent Z/E ratios (up to >19:1), and good enantioselectivity (up to 94% ee).
Cao et al. (2026) studied this question.