Synthetic method of peramivir intermediate

The invention relates to a synthetic method of a peramivir intermediate, in particular to a synthetic method of a key intermediate by adopting an anti-influenza drug, namely peramivir, wherein the key intermediate is (3aR,4R,6S,6aS)-4-[[(1,1-dimethyl ethoxy) carbonyl] amino]-3-(1'-ethyl propyl)-3a,5,6,6a-tetralin-tetrahydro-4H-cyclopentano[d]isoxazole-6-carboxylic acid ammonium tertiary butyl (compound IV). According to the synthetic method of peramivir intermediate, provided by the invention, (1S,4R)-(-)-[[(1,1-dimethyl ethoxy)carbonyl]amino]cyclopentyl-2-alkenyl-1- carboxylic acid methyl ester (compound I) is taken as the raw material (preparation reference patent is CN101367750B) to be subjected to ring-closure reaction with butyric imine acyl chloride under catalyzation of a metal catalyst, so that the target compound is formed. According to the synthetic method of peramivir intermediate, provided by the invention, the low-cost, easily available and efficient metal catalyst is used, in addition, compared with the conventional technological process, the synthetic method is obviously increased in the yield, the technological process is simple, and industrial large-scale production is facilitated.