Construction and Probing of Multisite Chiral Catalysts: Dendrimer Fixation of C2-Symmetrical Diphosphinerhodium Complexes
作者:Gerald D. Engel、Lutz H. Gade
DOI:10.1002/1521-3765(20020916)8:18<4319::aid-chem4319>3.0.co;2-l
日期:2002.9.16
spectrometry, which established their molecular masses of up to 20 700 amu. Metalation of the multi-site phosphines with [Rh(COD)(2)]BF(4) cleanly yielded the cationic rhododendrimers containing up to 32 metal centers (for the fourth generation species), representing the largest chiral phosphine dendrimer catalyst studied to date. The complete metalation of the chiral phosphine sites was demonstrated by
通过羧基连接的C(2)-手性吡咯配体(pyrphos = 3,4-bis(diphenylphosphino)pyrrolidine)与零第四代的反应,合成了一系列手性膦官能化的聚亚丙基亚胺(PPI)树状聚合物使用乙基-N,N-二甲基氨基丙基碳二亚胺(EDC)/ 1-羟基苯并三唑作为偶联剂的PPI。通过NMR光谱和元素分析以及FAB和MALDI-TOF质谱对得到的树枝状聚合物进行表征,所述树枝状聚合物的分子质量高达20700amu。用[Rh(COD)(2)] BF(4)金属化多位膦可干净地得到阳离子多晶树状聚合物,其中包含多达32个金属中心(对于第四代物种),代表了迄今为止研究的最大手性膦树状聚合物。通过(31)P NMR光谱和观察ABX自旋系统的配位移位AB部分(delta(A)= 33.9,delta(B)= 32.9;(1))证明了手性膦位点的完全金属化J(Rh,P)= 150,153Hz;(2)J(P,P)=