Experimental and Theoretical Analysis of the Photochemistry and Thermal Reactivity of Ethyl Diazomalonate and Its Diazirino Isomer. The Role of Molecular Geometry in the Decomposition of Diazocarbonyl Compounds
作者:Aneta Bogdanova、Vladimir V. Popik
DOI:10.1021/ja047824r
日期:2004.9.1
adopt a conformation in which carbonyl groups are almost orthogonal to the carbene plane. The outcome of the photolysis of ethyl diazomalonate depends on the wavelength of irradiation. Irradiation with 254 nm light results in the loss of nitrogen and the formation of dicarboethoxycarbene (5, Phi(254) = 0.31), while at longer wavelengths, diazirine 2 becomes an important byproduct (Phi(350) = 0.09). This
重氮丙二酸乙酯 (1) 或 3,3-二氮丙啶二羧酸乙酯在甲醇溶液中的光化学或热分解产生 OH 插入产物 6,而在这两种情况下均未检测到沃尔夫重排的产物。温度依赖性 (13)C NMR 谱的分析和 DFT B3LYP/6-311+G(3df,2p) 和 MP2/aug-cc-pVTZ//B3LYP/6-311+G(3df,2p) 的结果) 计算使我们得出结论,重氮二酯 1 主要存在于 Z,Z 构象中。相比之下,环状异丙叉重氮丙二酸酯 (3) 的光解(其重氮二羰基部分也具有 Z,Z 构型)导致干净的沃尔夫重排。这些观察使我们得出结论,重氮丙二酸酯的光分解方向不受基态构象的控制。1 和 3 去重氮化的势能面的量子力学分析表明,作为离散中间体的卡宾的形成受后者采用羰基几乎与卡宾正交的构象的能力控制飞机。重氮丙二酸乙酯光解的结果取决于照射波长。用 254 nm 光照射会导致氮损失并形成二碳乙氧基卡宾