rac-dimethyl (2-oxo-3-((4aR,6R,8aR)-4a,5',5'-trimethyl-5-oxooctahydro-1H-spiro[naphthalene-2,2'-[1,3]dioxan]-6-yl)propyl)phosphonate 在
sodium hydride 作用下,
以
乙二醇二甲醚 为溶剂,
以86%的产率得到rac-(3aR,5aR,9aR)-5',5',9a-trimethyl-3,3a,4,5,5a,8,9,9a-octahydrospiro[cyclopenta[a]naphthalene-7,2'-[1,3]dioxan]-2(6H)-one