title: Diboron as a reductant for nickel-catalyzed reductive coupling: rational design and mechanistic studies.
abstract: Diboron (B2pin2) has been identified as an efficient and environmentally benign reducing reagent for reductive coupling reactions for the first time, which enables the nickel-catalyzed reductive tetramerization of alkynes to be performed with high efficiency. Mechanistic and kinetic studies indicate that the facile reductive elimination to form the B-B bond from the dinuclear Ni-Ni complexes is responsible for the high efficiency. The activation enthalpy (ΔH(‡) = 56.5 kJ mol(-1)), entropy (ΔS(‡) = -128 J mol(-1) K(-1)) and the substituent effect (ρ = 1.43) on this reaction were obtained.
authors.affiliation: State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. hmhuang@licp.cas.cn.
authors.forename: Guoying
authors.initials: G
authors.lastname: Zhang
authors.forename: Yinjun
authors.initials: Y
authors.lastname: Xie
authors.forename: Zhengkun
authors.initials: Z
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Hanmin
authors.initials: H
authors.lastname: Huang