Kinetic Analysis and Sequencing of Si–H and C–H Bond Activation Reactions: Direct Silylation of Arenes Catalyzed by an Iridium-Polyhydride
作者:Miguel A. Esteruelas、Antonio Martínez、Montserrat Oliván、Enrique Oñate
DOI:10.1021/jacs.0c07578
日期:2020.11.11
addition of the coordinated bond and the subsequent reductive elimination of H2. Complexes 2-4 activate a C-H bond of symmetrically and asymmetrically substituted arenes to form silylated arenes and to regenerate 1. This sequence of reactions defines a cycle for the catalytic direct C-H silylation of arenes. Stoichiometric isotopic experiments and the kinetic analysis of the transformations demonstrate
饱和三氢化物 IrH3κ3-P,O,P-[xant(PiPr2)2]} (1; xant(PiPr2)2 = 9,9-二甲基-4,5-双(二异丙基膦基)呫吨)配位 Si-三乙基硅烷、1,1,1,3,5,5,5-七甲基三硅氧烷和三苯基硅烷的 H 键生成 σ-配合物 IrH3(η2-H-SiR3)κ2-cis-P,P-[xant(PiPr2 )2]},其演变为二氢化物-甲硅烷基衍生物 IrH2(SiR3)κ3-P,O,P-[xant(PiPr2)2]} (SiR3 = SiEt3 (2), SiMe(OSiMe3)2 (3) , SiPh3 (4)) 通过配位键的氧化加成和随后的 H2 还原消除。配合物 2-4 激活对称和不对称取代芳烃的 CH 键以形成甲硅烷基化芳烃并再生 1。该反应序列定义了芳烃催化直接 CH 甲硅烷基化的循环。化学计量同位素实验和转化动力学分析表明,CH 键断裂是催