Thermolysis of 4-acetoxymethylene-2-[2-benzyloxy-2-(5-methoxy-3-methylbenzo-cyclobuten-1-yl] ethyl-2-methylcyclopentan-1, 3-dione 1-ethylene ketal (21) gave the stachane-type tetracyclic compound (24), whose deketalization afforded 26, a potential synthetic intermediate to the quassinoid klaineanone (1).
4-acetoxymethylene-2-[2-benzyloxy-2-(5-methoxy-3-methylbenzo-cyclobuten-1-yl] ethyl-2-methylcyclopentan-1, 3-dione 1-ethylene ketal (21)热分解后得到了司他烷型四环化合物 (24),其脱酮化后得到了 26,这是一种潜在的
槲皮苷 klaineanone (1) 合成中间体。