ent-3α,13-diacetoxy-10β-hydroxy-15-oxo-20-norgibberellane-7,19-dioic acid 7-methyl ester 19,10-lactone 、
碘甲烷 在
potassium hydride 作用下,
以71%的产率得到methyl (1R,2R,5S,8R,9S,10R,11S,12S)-5,12-diacetyloxy-6,6,11-trimethyl-7,16-dioxo-15-oxapentacyclo[9.3.2.15,8.01,10.02,8]heptadecane-9-carboxylate