重氮甲烷 、
(Z)-2-甲基-2-丁烯酸(3aR)-2,3,3a,4,5,7,9a,9balpha-八氢-4beta,9abeta-二羟基-6,9-二甲基-3-亚甲基-2,7-二氧代薁并[4,5-b]呋喃-5alpha-基酯 以
乙醚 为溶剂,
生成 [(3'aR,4'R,5'R,9'aR,9'bS)-4',9'a-dihydroxy-6',9'-dimethyl-2',7'-dioxospiro[3,4-dihydropyrazole-5,3'-3a,4,5,9b-tetrahydroazuleno[4,5-b]furan]-5'-yl] (Z)-2-methylbut-2-enoate