作者:Katherine M. Broadus、Steven R. Kass
DOI:10.1039/a905868k
日期:——
Benzocyclobutenone enolate (1a) was synthesized by deprotonating its conjugate acid with fluoride ion in the gas phase using a Fourier transform mass spectrometer. Reactions of 1a were explored and C-alkylation was found to be greatly preferred over oxygen attack. Thermodynamic properties (ÎH°acid(1) = 360.3 ± 2.1 kcal molâ1, EA(benzocyclobutenyl radical) = 1.90 ± 0.10 eV, and BDE(CâH) = 90.5 ± 3.1 kcal molâ1) also were measured. The results are contrasted to ab initio calculations on cyclobutanone, benzocyclobutenone, and cyclobutenone enolates. Natural bond orbital and Bader analyses are reported too. Given our gas phase and computational results, we were able to devise conditions for the generation and trapping of 1a in tetrahydrofuran despite previous failings reported in the literature.
利用傅立叶变换质谱仪,通过在气相中用氟离子对其共轭酸进行去质子化,合成了苯并环丁烯酮烯醇盐(1a)。研究人员对 1a 的反应进行了探讨,发现 C-烷基化反应比氧攻击反应更受青睐。此外,还测量了热力学性质(δH°acid(1) = 360.3 ±Â 2.1 kcal molâ1、EA(苯并环丁烯基) = 1.90 ±Â 0.10 eV 和 BDE(CâH) = 90.5 ±Â 3.1 kcal molâ1)。这些结果与环丁酮、苯并环丁烯酮和环丁烯酮烯醇化合物的 ab initio 计算结果进行了对比。此外,还报告了自然键轨道和 Bader 分析。鉴于我们的气相和计算结果,我们能够设计出在四氢呋喃中生成和捕获 1a 的条件,尽管之前有文献报道过失败的情况。