Mechanistic studies of catalytic olefin dimerization reactions using electrophilic eta(3)-allyl-palladium(II) complexes
Mechanistic studies of catalytic olefin dimerization reactions using electrophilic eta(3)-allyl-palladium(II) complexes
复制标题
DOI：
10.1021/ja9602354
复制
发表时间：
1996-07-03
影响因子：
15
通讯作者：
Brookhart, M
中科院分区：
文献类型：
--
作者：
DiRenzo, GM;White, PS;Brookhart, M
研究了[(C3H5)Pd(L)(PR(3))](+)[BAR‘(4)](-)(Ar’=[3，5-C6H3(CF3)(2)]；L=OEt(2)，H2O；R环己基(Cy)，正丁基((N)Bu))型阳离子ETA3-烯丙基钯配合物对烯烃的二聚反应。这些配合物在-80℃下与乙烯或丙烯酸甲酯反应，失去L，生成ETa(2)-烯烃配合物[(C3H5)Pd(eta(2)-olefin)(PR(3))](+)[BAr‘(4)](-)(烯烃=H_2C=CH_2，CH_2=CH_3(O)OCH_3)。升温时，发生烯丙基-烯烃偶联反应。乙烯的二聚反应在0℃下迅速发生，乙基乙烯中间体[(C2H5)Pd(C2H4)2(PCy(3))](+)[bar‘(4)](-)。丙烯酸甲酯反应生成稳定的丙烯酸酯络合物[(CH3O(O)CCH2CH2)Pd(CH2=CHC(O)OCH3)(PR(3))(+)[BAr‘(4)](-)，，它是室温下发生的丙烯酸甲酯二聚反应的催化剂静止态，主要生成反式-2-己二酸二甲酯。
The dimerization of olefins by well-defined cationic eta 3-allyl-palladium complexes of the type [(C3H5)Pd(L)(PR(3))](+)[BAr'(4)](-) (Ar' = [3,5-C6H3(CF3)(2)]; L = OEt(2), H2O; R cyclohexyl (Cy), n-butyl ((n)Bu)) has been studied. These complexes react with ethylene or methyl acrylate at -80 degrees C with loss of L to form the eta(2)-olefin complexes [(C3H5)Pd(eta(2)-olefin)(PR(3))](+)[BAr'(4)](-) (olefin = H2C=CH2, CH2=CHC(O)OCH3). Upon warming, allyl-olefin coupling occurs. The dimerization of ethylene occurs rapidly at 0 degrees C with an observable ethyl-ethylene intermediate [(C2H5)Pd(C2H4)2(PCy(3))](+)[BAr'(4)](-). Methyl acrylate reacts to form a stable acrylate chelate complex, [(CH3O(O)CCH2CH2)Pd(CH2=CHC(O)OCH3)(PR(3))(+)[BAr'(4)](-), which is the catalyst resting state for methyl acrylate dimerization which occurs at room temperature to give predominantly trans-dimethyl-2-hexenedioate.