Rhodium/diene-catalyzed tandem 1,4-shift/1,4-addition of (E)-1,2-diphenylethenylboronic acid to enones: density functional theory modeling and asymmetric catalysis
Rhodium/diene-catalyzed tandem 1,4-shift/1,4-addition of (E)-1,2-diphenylethenylboronic acid to enones: density functional theory modeling and asymmetric catalysis
复制标题
DOI：
10.1039/c2sc01093c
复制
发表时间：
2012-03
期刊：
影响因子：
8.4
通讯作者：
K. Sasaki;T. Nishimura;R. Shintani;E. Kantchev;Tamio Hayashi
中科院分区：
文献类型：
--
作者：
K. Sasaki;T. Nishimura;R. Shintani;E. Kantchev;Tamio Hayashi
在二烯/铑催化剂存在下，（E）-1，2-二苯基乙烯基硼酸与2-环己烯酮的共轭加成导致引入2-（（E）-2-苯基乙烯基）苯基的重排产物。该催化循环涉及从1，2-二苯基乙烯基铑中间体的1，4-Rh移位，以形成新的2-（（E）-2-苯基乙烯基）苯基铑中间体。密度泛函理论计算表明，Rh（III）氢化物中间体的1，4-Rh位移是通过C-H氧化加成和还原消除反应发生的。1，4-位移过渡态和碳氢化过渡态的相对ΔG ε与实验观察到的选择性符合得很好。
The conjugate addition of (E)-1,2-diphenylethenylboronic acid to 2-cyclohexenone in the presence of a diene/rhodium catalyst leads to a rearranged product incorporating a 2-((E)-2-phenylethenyl)phenyl group. The catalytic cycle involves a 1,4-Rh shift from the 1,2-diphenylethenylrhodium intermediate to form a new 2-((E)-2-phenylethenyl)phenylrhodium intermediate. DFT calculations demonstrate that the 1,4-Rh shift occurs via C–H oxidative addition and reductive elimination to/from a distorted square-pyramidal Rh(III)-hydride intermediate. The relative ΔG≠ of the 1,4-shift and carborhodation transition states are in good agreement with the experimentally observed selectivity.