(+/-)-Bakkenolide A was prepared in five steps from ethyl 4-benzyloxyacetoacetate by sequential alkylations with tiglyl bromide nd cis-5-bromo-1,3-pentadiene, followed by an intramolecular Diels-Alder reaction as the key step. The known 7-epibakkenolide A and novel 10-epi- and 7,10-diepibakkenolide A stereoisomers were obtained as minor byproducts.
(+/-)-Bakkenolide A分五个步骤由4-苄氧基
乙酰乙酸乙酯通过与间苯二甲酰
溴和cis-5-bromo-1,3-pentadiene顺序烷基化而制备,然后进行分子内Diels-Alder反应作为关键步骤。作为次要副产物,获得了已知的7-表柏油基内酯A和新型的10-表-和7,10-
二苯甲酮内酯A立体异构体。