N-Heterocyclic Carbene Ligand-Controlled Regioselectivity for Nickel-Catalyzed Hydroarylation of Vinylarenes with Benzothiazoles
作者:Rui-Peng Li、Zheng-Wang Shen、Qin-Jia Wu、Jie Zhang、Hong-Mei Sun
DOI:10.1021/acs.orglett.9b01645
日期:2019.7.5
A facile regioselective switch for nickel-catalyzed hydroarylation of vinylarenes with benzothiazoles has been developed, which relies on the simple structural variation of novel Ni(II) complexes of the type Ni(NHC)[P(OR)3]Br2. Using magnesium turnings as the reductant, Ni(IMes)[P(OEt)3]Br2 afforded branched products, while Ni(IPr*OMe)[P(OEt)3]Br2 created steric demand to afford linear products. This
enantioselective secondary benzylic C–Hborylation using benzothiazole as the directing group. Various monosubstituted 2-arylalkylbenzo[d]thiazole were well-tolerated, affording the corresponding products in moderate to good yields with good enantioselectivity. The C–B bond in one borylated product could undergo stereospecific transformations to form a series of C–C and C–heteroatom bonds.