Cycloadditions of 4-pyrones. An approach to colchicine
作者:Bill J. McBride、Michael E. Garst
DOI:10.1016/s0040-4020(01)80383-5
日期:1993.4
The 4-pyrone, [5-acetoxy-4-oxo-4-pyran-2-yl]carbonyl chloride was coupled with malonate anion of bis(2,2,2-trichloroethyl) 2-ethenyl-3,4,5-trimethoxybenzylpropanedioate and analogs thereof. These adducts then underwent intramolecular thermal cyclizations (61-100% yield) to form the two fused seven member rings of the carbon skeleton of colchicine. The malonate moiety was deprotected and decarboxylated
将4-吡喃酮,[5-乙酰氧基-4-氧代-4-吡喃-2-基]羰基氯与双(2,2,2-三氯乙基)2-乙烯基-3,4,5-的丙二酸根阴离子偶联。三甲氧基苄基丙二酸酯及其类似物。然后对这些加合物进行分子内热环化(产率61-100%),形成秋水仙碱碳骨架的两个稠合的七元环。将丙二酸酯部分脱保护并定量脱羧,以提供所需的环系统,该环系统在C环中包含从C7a至C11的桥连醚,以及在7位的酮。除去作为H 2 O的桥联醚将得到所需的对pol酮。我们移除以太桥的尝试未成功。