Cross-Coupling Reaction of Alkenyl Sulfoximines and Alkenyl Aminosulfoxonium Salts with Organozincs by Dual Nickel Catalysis and Lewis Acid Promotion.

In this article, the cross-coupling reaction (CCR) of exocyclic, axially chiral, and acyclic alkenyl (N-methyl)sulfoximines with alkyl- and arylzincs is described The CCR generally requires dual Ni catalysis and MgBr promotion, which is effective in diethyl ether but not in THF. NMR spectroscopy revealed a complexation of alkenyl sulfoximines by MgBr in diethyl ether, which suggests an acceleration of the oxidative addition through nucleofugal activation. The CCR of alkenyl sulfoximines generally proceeds in the presence of Ni(dppp)Cl as a precatalyst and MgBr with alkyl- and arylzincs with a high degree of stereoretention at the C and the S atom. CCR of axially chiral alkenyl sulfoximines with Ni(PPh ) Cl as a precatalyst and ZnPh does not require salt promotion and is stereoretentive. The reaction with Zn(CH SiMe ) , however, demands salt promotion and is not stereoretentive. CCR of axially chiral α-methylated alkenyl sulfoximines afforded persubstituted axially chiral alkenes with high selectivity. Alkenyl (N-triflyl)sulfoximines engage in a stereoretentive CCR with Grignard reagents and Ni(PPh ) Cl . Ni-Catalyzed and MgBr -promoted CCR of E-configured acyclic alkenyl sulfoximines and aminosulfoxonium salts with ZnPh and Zn(CH SiMe ) is stereoretentive with Ni(dppp)Cl and Ni(PPh ) Cl . CCRs of acyclic alkenyl sulfoximines and alkenyl aminosulfoxonium salts, carrying a methyl group at the α position, take a different course and give alkenyl sulfinamides under stereoretention at the S and C atom. CCR of acyclic, exocyclic, and axially chiral alkenyl sulfoximines has been successfully applied to the stereoselective synthesis of homoallylic alcohols, exocyclic alkenes, and axially chiral alkenes, respectively.