重氮甲烷 、
Methyl (28-Hydroxy-23,28-dioxoolean-12-en-3β-yl 3',4'-O-oxydiethylidene-β-D-glucopyranoside)uronate 以
甲醇 、
乙醚 为溶剂,
以88%的产率得到methyl (3S,3aR,3bR,5aR,5bS,7aS,13bR,15aS)-3-hydroxy-3a,5a,5b,10,10,13b-hexamethyl-2,3,3a,4,5,5a,5b,6,7,8,9,10,11,11a,13,13a,13b,14,15,15a-icosahydropiceno[3,4-b]furan-7a(3bH)-carboxylate