Origins of differences in reactivities of alkenes, alkynes, and allenes in [Rh(CO)2Cl]2-catalyzed (5 + 2) cycloaddition reactions with vinylcyclopropanes.
Origins of differences in reactivities of alkenes, alkynes, and allenes in [Rh(CO)2Cl]2-catalyzed (5 + 2) cycloaddition reactions with vinylcyclopropanes.
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DOI：
10.1021/ja076444d
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发表时间：
2008-02
影响因子：
15
通讯作者：
Zhi‐Xiang Yu;Paul Ha‐Yeon Cheong;Peng Liu;Claude Y. Legault;P. Wender;K. Houk
中科院分区：
文献类型：
--
作者：
Zhi‐Xiang Yu;Paul Ha‐Yeon Cheong;Peng Liu;Claude Y. Legault;P. Wender;K. Houk
铑二聚体[Rh（CO）2Cl]2能有效地催化乙烯基环丙烷与炔和联烯的分子内和分子间（5 + 2）反应，但对烯烃无催化作用。这种反应性的差异归因于烯烃还原消除的困难。计算的还原消除跃迁结构表明，与乙烯相比，乙炔和丙二烯中第二个π轨道的参与使势垒降低了9 ~ 15 kcal/mol，而乙烯不可能发生这种相互作用。
Rhodium dimer [Rh(CO)2Cl]2 efficiently catalyzes the intra- and intermolecular (5 + 2) reactions of vinylcyclopropanes with alkynes and allenes, but not alkenes. This difference in reactivity is attributed to the difficulty of reductive elimination for the alkene. The computed reductive elimination transition structures show that the participation of the second π-orbital in acetylene and allene reduces the barrier by 9∼15 kcal/mol, compared to ethylene, for which no such interactions are possible.