Ni-Catalyzed Enantioconvergent Coupling of Epoxides with Alkenylboronic Acids:Construction of Oxindoles Bearing Quaternary Carbons

We have developed a nickel-nickel/bisphosphinecatalyzed stereoconvergent cross-coupling reaction of epoxides with alkenylboronic acids.Racemic spiroepoxyoxindoles were converted to chiral homoallylic alcohols bearing quaternary carbon stereogenic centers via a stereoablative enantioconvergent transformation.The subsequently fabricated oxindoles-carrying quaternary carbon products were obtained in good yields and enantioselectivity.A wide range of substrates and alkenylboronic acids was tolerated under the catalytic system.This reaction provided a rare example of a nickelcatalyzed enantioselective cross-coupling reaction of tertiary alkyl electrophiles and an enantioconvergent transformation of racemic epoxides,beneficial as a low-cost,sustainable,and efficient catalyst in the preparation of chiral oxindole-containing natural and pharmaceutical compounds.