methyl 2-((2R,5S,6S)-6-(((tert-butyldiphenylsilyl)oxy)methyl)-5-(2-fluoro-N-methyl-5-nitrobenzamido)-5,6-dihydro-2H-pyran-2-yl)acetate 在
cesium fluoride 作用下,
以
N,N-二甲基甲酰胺 为溶剂,
以73%的产率得到methyl 2-((2R,4aS,12aS)-5-methyl-8-nitro-6-oxo-2,4a,5,6,12,12a-hexahydrobenzo[b]pyrano[3,2-f][1,5]-oxazocin-2-yl)acetate