The thermal [4+2] cycloadditions of 3-acetyl-, 3-carbamoyl, and 3-ethoxycarbonylcoumarins with 2,3-dimethyl-1,3-butadiene under solvent free conditions are reported, as well as the epoxidation reactions of some adducts. Discussion is focused on the structural features of the Diels-Alder adducts and their epoxides, based upon NMR, X-ray, and mass spectral data, and supported by ab initio theoretical calculations.
报告了在无溶剂条件下,3-乙酰基、3-
氨基甲酰基和 3-乙氧羰基
香豆素与
2,3-二甲基-1,3-丁二烯的热[4+2]环加成反应,以及一些加成物的环氧化反应。根据核磁共振、X 射线和质谱数据,并在 ab initio 理论计算的支持下,重点讨论了 Diels-Alder 加合物及其
环氧化物的结构特征。