P−C and C−C Bond Formation by Michael Addition in Platinum-Catalyzed Hydrophosphination and in the Stoichiometric Reactions of Platinum Phosphido Complexes with Activated Alkenes
作者:Corina Scriban、David S. Glueck、Lev N. Zakharov、W. Scott Kassel、Antonio G. DiPasquale、James A. Golen、Arnold L. Rheingold
DOI:10.1021/om060631n
日期:2006.11.1
Decomposition of A and B gave unidentified platinum dialkyls (C), tentatively formulated as Pt(diphos)(R‘)(CH(X)R‘ ‘). The complex Pt(dppe)(Me)(CH(Me)CO2t-Bu) (21), a model for A, B, and C, was generated either from Pt(dppe)(Cl)(CH(Me)CO2t-Bu) (20) and ZnMe2 or from Pt(dppe)(Me)(Cl) (19) and ZnBr(CH(Me)CO2t-Bu)·THF; complexes 20 and 21 did not react with tert-butyl acrylate. These observations are consistent
我们最近提出了一种铂催化的活化烯烃的氢磷酸化的新机制,其中中间体氢化物配合物Pt(diphos)(PR 2)(H)(1)中的磷配体对烯烃H 2 C CH(的亲核攻击)X)(X = CN或CO 2 R)得到两性离子Pt(diphos)(H)(PR 2 CH 2 CHX)(2),该两性离子包含阳离子Pt中心和带有稳定的侧链的膦配体。随后的涉及Pt-H和碳负离子的C-H键形成将产生产物R 2 PCH 2 CH 2 X(3)并再生催化剂,同时碳负离子攻击另一种烯烃会产生衍生自一种以上烯烃的副产物,例如R 2 P(CH 2 CH(X))n CH 2 CH 2 X(7)。研究了该机理的几种测试方法以及产物和副产物形成的相关途径。尝试用另一种亲电子试剂捕获拟议的碳负离子导致了仲膦,丙烯酸叔丁酯和苯甲醛的Pt催化三组分偶联的发展,产生了功能化的膦R 2 PCH 2 CH(CO 2 t -Bu) (CHPh(OH))(R