title: Catalytic asymmetric hydroalkenylation of vinylarenes: electronic effects of substrates and chiral N-heterocyclic carbene ligands.
abstract: An asymmetric tail-to-tail cross-hydroalkenylation of vinylarenes with terminal olefins was achieved by catalysis with NiH complexes bearing chiral N-heterocyclic carbenes (NHCs). The reaction provides branched gem-disubstituted olefins with high enantioselectivity (up to 94 % ee) and chemoselectivity (cross/homo product ratio: up to 99:1). Electronic effects of the substituents on the vinylarenes and on the N-aryl groups of the NHC ligands, but not a π,π-stacking mechanism, assist the steric effect and influence the outcome of the cross-hydroalkenylation.
authors: Department of Chemistry, South University of Science and Technology of China (SUSTC).; Center of Novel Functional Molecules, Shenzhen Research Institute, The Chinese University of Hong Kong (CUHK).. jasonhcy@sustc.edu.cn, jasonhcy@cuhk.edu.hk.
authors: Chun-Yu
authors: CY
authors: Ho
authors: Chun-Wa
authors: CW
authors: Chan
authors: Lisi
authors: L
authors: He
keywords: N-heterocyclic carbenes; asymmetric catalysis; hydroalkenylation; nickel; olefins