在线阅读 --自然科学版 2011年3期《CuI催化炔基苯甲醛分子内环化反应的理论研究》
CuI催化炔基苯甲醛分子内环化反应的理论研究--[在线阅读]
张金生, 陈卓, 谢辉
贵州师范大学化学与材料科学学院, 贵州贵阳 550001
起止页码: 269--274页
DOI:
摘要
应用量子化学密度泛函理论(DFT)和自洽反应场极化连续介质模型,在B3LYP/6-311G(d,p)计算水平上对CuI催化炔基苯甲醛和甲醇反应合成环烯基醚进行了理论研究.结果表明,甲氧基环内烯醚是热力学优势产物,其总反应包括炔基的活化、炔-羰环化反应、醇-羰亲核反应、质子传载反应和催化剂解离等步骤.炔-羰环化反应是速控步骤,CuI的催化作用使该步骤过渡态的相对吉布斯自由能下降了163.9 kJ/mol.CuI催化作用的本质在于,Cu与炔基配位,使炔基反键轨道πc1-c2**能级降低,使πc1-c2**与羰基氧原子的孤电子占据轨道LP-(2p)O1的能级差减小.甲醇发挥亲核试剂和质子传载双重作用.

Theoretical Study on the CuI-catalyzed Intramolecular Cyclization of Alkynylbenzaldehydes
ZHANG Jinsheng, CHEN Zhuo, XIE Hui
School of Chemistry and Material Science, Guizhou Normal University, Guizhou Guiyang 550001, China
Abstract:
By means of density functional theory(DFT) and self-consistent reaction field of polarizable continuum model approach,the one-pot synthesis mechanism of cyclic alkenyl ethers via intramolecular cyclization of o-alkynylbenzaldehydes catalyzed by CuI has been investigated.The results suggest that the regioselectivity is thermodynamic favoring 6-endo-dig cyclization,and the overall reaction includes the activation of the substrate,an intramolecular cyclization step,a nucleophilic attack of the methanol on the carbonyl carbon,proton migration and the catalyst reproduction.The intramolecular cyclization is the rate-controlling step in which CuI decreases the relative Gibbs free energy of the transition state by 163.9 kJ/mol.The catalysis essential of CuI is the coordination of copper(I) to the triple bond which can remarkablely decrease the orbital energy of πc1-c2* and the orbital energy-gap between πc1-c2* and LP-(2p)O1.MeOH plays dual functions:as a nucleophile to attack on carbonyl carbon,as a proton shuttle to transport a proton from a nucleophile to the alkynyl-carbon.

收稿日期: 2010-12-18
基金项目: 国家自然科学基金(20862004);贵州省科学技术基金(黔科合J字[2009]2241号)

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