16β,17,18-trihydroxy-ent-kauran-19-oic acid 在
chromium(VI) oxide 、
硫酸 作用下,
以
吡啶 为溶剂,
反应 14.0h,
生成 (4S,4'S,4a'R,6a'S,9'R,11a'R,11b'R)-2,2,11b'-trimethyldodecahydro-7'H-spiro[[1,3]dioxolane-4,8'-[6a,9]methanocyclohepta[a]naphthalene]-4'-carboxylic acid