重氮甲烷 、
(3S,4S)-4-[2-[(1,1-dimethylethyl)diphenylsilyloxy]ethyl]tetrahydro-2-methoxyl-3-methyl-2-furanacetaldehyde 、
2,6-dihydroxy-4-[(2R)-2-hydroxyheptyl]benzoic acid 在
Dowex 50WX
8-400-H+ ion exchange resin 作用下,
以
甲醇 、
乙醚 为溶剂,
反应 60.0h,
以30%的产率得到methyl (2S,3S,3'aS,4S,5'R)-4-[2-[(1,1-dimethylethyl)diphenylsilyloxy]ethyl]-3',3'a,4,5,5',6'-hexahydro-8'-hydroxy-3-methyl-5'-pentyl-spiro[furan-2(3H),2'-[2H]pyrano[2,3,4-de][1]benzopyran]-9'-carboxylate