Hansen Jorn, Li Bo, Dikarev Evgeny, Autschbach Jochen, Davies Huw M L
Department of Chemistry, Emory University, 440 Atwood Hall, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
J Org Chem. 2009 Sep 4;74(17):6564-71. doi: 10.1021/jo900998s.
The catalytic activity of heterobimetallic Bi-Rh paddlewheel carboxylate complexes has been evaluated for the first time in the context of metal carbenoid chemistry. The Bi-Rh carboxylate complexes were found to effectively catalyze both cyclopropanation reactions and C-H insertions as well as reactions involving ylide intermediates with similar selectivity profiles to analogous dirhodium complexes. The heterometallic complex BiRh(O(2)CCF(3))(3)(O(2)CCH(3)) was found to be approximately 1600 times less reactive than its homometallic analogue Rh(2)(O(2)CCF(3))(3)(O(2)CCH(3)) toward the decomposition of methyl phenyldiazoacetate. The observed difference in reactivity is in good agreement with a computational model system where axial coordination to the second rhodium active site is considered for the dirhodium catalyst.
在金属卡宾化学背景下，首次对异双金属Bi-Rh桨轮羧酸盐配合物的催化活性进行了评估。发现Bi-Rh羧酸盐配合物能有效催化环丙烷化反应、C-H插入反应以及涉及叶立德中间体的反应，其选择性与类似的二铑配合物相似。发现异金属配合物BiRh(O₂CCF₃)₃(O₂CCH₃)对苯基重氮乙酸甲酯分解的反应活性比其同金属类似物Rh₂(O₂CCF₃)₃(O₂CCH₃)低约1600倍。观察到的反应活性差异与一个计算模型体系高度吻合，在该模型体系中，二铑催化剂考虑了与第二个铑活性位点的轴向配位。
