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Published on: June 21, 2017
Mechanism of Synergistic Cu(II)/Cu(I)-Mediated Alkyne Coupling: Dinuclear 1,2-Reductive Elimination after Minimum
Xiaotian Qi1, Ruopeng Bai2, Lei Zhu1
1School of Chemistry and Chemical Engineering, Chongqing University , Chongqing 400030, People's Republic of China.
Abstract:
An in-depth theoretical study of synergistic Cu(II)/Cu(I)-mediated alkyne coupling was performed to reveal the detailed mechanism for C-C bond formation, which proceeded via an unusual dinuclear 1,2-reductive elimination. Because the reactant for dinuclear 1,2-reductive elimination was calculated to be triplet while the products were singlet, the minimum energy crossing point (MECP) was introduced to the Cu/TMEDA/alkyne system to clarify the spin crossing between triplet state and singlet state potential energy surfaces. Computational results suggest that C-H bond cleavage solely catalyzed by the Cu(I) cation is the rate-determining step of this reaction and Cu(II)-mediated dinuclear 1,2-reductive elimination after the MECP is a facile process. These conclusions are in good agreement with our previous experimental results.
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