Investigation of the Mechanism for the Preparation of 6-Phenyl-2,4-dioxotetrahydropyrans by the Potassium Carbonate Promoted Condensation between Acetoacetate Esters and Benzaldehyde
作者:Brad Andersh、Elizabeth T. Nguyen、Ryan J. Van Hoveln、Dylan K. Kemmerer、David A. Baudo、Jessica A. Graves、Mollie E. Roark、Wayne B. Bosma
DOI:10.1021/jo400213s
日期:2013.5.3
4-dioxotetrahydropyran. Based upon results from deuterium exchange experiments, carbon-13 labeling experiments, 1H NMR monitoring studies, and reactivity studies, our proposed mechanism for this reaction involves deprotonation at the α-carbon, intramolecular proton transfer to form a γ-anion, addition of the resulting γ-anion to the carbonyl carbon of benzaldehyde, and intramolecular transesterification.
在醇溶剂中用碳酸钾处理苯甲醛和乙酰乙酸酯是通过γ-C-烷基化而不是α-C-烷基化进行的,导致形成6-苯基-2,4-二氧代四氢吡喃。根据氘交换实验,碳13标记实验,1 H NMR监测研究和反应性研究的结果,我们提出的该反应机理涉及α-碳的去质子化,分子内质子转移形成γ-阴离子,添加生成的γ阴离子与苯甲醛的羰基碳发生分子内酯交换反应。