Chemical means were used to achieve the epimerization at C-6 of 6α-eudesmanolides, with several functionalizations, to 7β-eudesmanolides. The process consists of the LiAlH4 reduction of a 6α-lactone, selective acetylation of the hydroxymethylene group at C-12, oxidation and reduction at C-6 to epimerize this carbon, deacetylation at C-12 and final formation of a 6β-lactone with RuH2(Ph3P)4. The whole
使用
化学方法实现了具有一些功能化的6α-大麦醇内酯在C-6的差向异构化为7β-大麦醇内酰胺。该方法包括LiAlH 4还原6α-内酯,在C-12处羟甲基的选择性乙酰化,在C-6处氧化和还原以使该碳异构化,在C-12处脱乙酰基和最终形成6β-内酯。含RuH 2(Ph 3 P)4。整个过程产生近40%的6β-内酯,限制步骤是用
钌试剂(58和53%)进行氧化。