Conjugate phosphination of cyclic and acyclic acceptors using Rh(I)–phosphine or Rh(I)–carbene complexes. Probing the mechanism with chirality at the silicon atom or the phosphorus atom of the Si–P reagent
作者:Verena T. Trepohl、Roland Fröhlich、Martin Oestreich
DOI:10.1016/j.tet.2009.04.038
日期:2009.8
The Rh(I)-catalyzed conjugate phosphinyl transfer from an Si–P reagent to an electron-deficient acceptor requires individual protocols for cyclic and acyclic α,β-unsaturated carbonyls and carboxyls. While 1,4-addition to cyclic acceptors is catalyzed by a Rh(I)–phosphine complex, a Rh(I)–carbene complex is needed to promote conjugate phosphination of acyclic acceptors. General procedures for both systems
从Si-P试剂到缺电子受体的Rh(I)催化的共轭亚膦酰基转移需要针对环状和非环状α,β-不饱和羰基和羧基的单独方案。尽管Rh(I)-膦配合物可催化向环受体加成1,4-,但需要Rh(I)-卡宾配合物来促进非环受体的共轭磷酸化。报告了这两个系统的一般步骤。除了单膦源化的Si-P试剂作为次膦化物来源外,具有两个Si-P单元的dppe-以及dppp衍生的试剂也参与了该反应。这种Rh(I)催化Si-P试剂活化的机制仍在争论中。使用对映纯硅立体异构和外消旋磷立体异构Si-P试剂进行的对照实验支持催化从重金属化而不是氧化加成开始。包括本研究中使用的Si-P化合物的制备和全部表征数据。