ethyl 4-oxoalkanoates via the oxidation of the intermediate 1,2-dialkylcyclopropanols having a protected carbonyl group in an aliphatic chain. Intramolecular acetalization of these epoxy dicarbonyl compounds gave alkylated 6,8-dioxabicyclo[3.2.1]octan-2-ones in good yields. The latter were found suitable to be precursors for (±)-endo-brevicomin and its 2-hydroxy derivative, as well as (±)-endo-isobrevicomin
由4-氧代链烷酸
乙酯的
乙缩醛通过氧化在脂肪族链中具有被保护的羰基的中间体1,2-二烷基
环丙醇制备1-(2-氧代芳基)-1,4-烷二酮。这些环氧二羰基化合物的分子内
缩醛化以良好的收率得到烷基化的
6,8-二氧杂双环[3.2.1]辛烷-2-酮。发现后者适合作为(±)-内-brevicomin及其2-羟基衍
生物以及(±)-内-异brevicomin和(±)-额叶青素的前体。