Cascade reactions of cyclic dienolates 1 with enantiopure Michael acceptors 2 lead to 3. Oxidation of 3 under Baeyer-Villiger conditions gave solely the lactones 4. The double-push-pull substituted cyclopropane moiety of 4a was selectively opened upon hydrogenolysis to yield oxabicyclo[3.3.1]nonane 6. Reduction of lactone 4a gave the hemiacetal 7. It was converted to the vinylcyclopropane 10 which was hydrogenated to give the highly functionalized cycloheptane 11 and oxabicyclo[3.2.1]octanes 12.
环二
酮酸酯 1 与对映纯迈克尔受体 2 发生级联反应,生成 3。4a 的双推挽取代
环丙烷分子在氢解过程中被选择性打开,生成氧杂双环[3.3.1]
壬烷 6。还原内酯 4a 得到
半缩醛 7。将其转化为
乙烯基环丙烷 10,再将其氢化,得到高度官能化的
环庚烷 11 和氧杂
双环[3.2.1]辛烷 12。