Catalysis of Enantioselective [2+1]-Cycloaddition Reactions of Ethyl Diazoacetate and Terminal Acetylenes Using Mixed-Ligand Complexes of the Series Rh<sub>2</sub>(RCO<sub>2</sub>)<i><sub>n</sub></i> (L*<sub>4</sub><sub>-</sub><i><sub>n</sub></i>). Stereochemical Heuristics for Ligand Exchange and Catalyst Synthesis
作者:Yan Lou、Travis P. Remarchuk、E. J. Corey
DOI:10.1021/ja052254w
日期:2005.10.1
mixed Rh(2)(II) complexes containing bridging acetate and R,R-diphenyl-N-triflylimidazolidinone (DPTI) ligands (1, 2, and 9-19), and their function as enantioselective catalysts for the conversion of ethyl diazoacetate and terminal acetylenes to chiral cyclopropenes. Of these catalysts, 1 and 10 functioned with the highest enantioselectivity, in accord with a mechanistic model in which one of the ligand
本文描述了含有桥接乙酸盐和 R,R-二苯基-N-三氟甲磺酸基咪唑烷酮 (DPTI) 配体 (1、2 和 9-19) 的混合 Rh(2)(II) 配合物的合成,以及它们作为对映选择性催化剂的功能重氮乙酸乙酯和末端乙炔转化为手性环丙烯。在这些催化剂中,1 和 10 以最高的对映选择性起作用,与其中一个配体桥在中间体 Rh-卡宾配合物中断裂的机理模型一致。合成结果可以得出关于合成乙酸酯-DPTI 复合物的动力学和热力学有利途径的结论。正如模型所预期的那样,一种仅具有两个抗 DTBTI 桥 (23) 的新 C(2) 对称复合物被证明是一种高效的手性催化剂。