合成路线1

The reaction of oxirane (I) with vinylmagnesium bromide in THF gives 1-(4-fluorophenoxy)-4-penten-2(S)-ol (II), which is treated with ethyl vinyl ether and mercuric trifluoroacetate to yield the vinyl ether (III). The cyclization of (III) by means of Grubb's catalyst in refluxing benzene affords the dihydrofuran (IV), which is treated with benzenesulfinic acid in dichloromethane to give the sulfone (V). The reaction of (V) with the acetylenic tetrahydropyranyl ether (VI) by means of isopropylmagnesium bromide in THF yields the expected addition product (VII), which is treated with TsOH to eliminate the tetrahydropyranyl group and provide the alcohol (VIII). The condensation of (VIII) with N,O-bis (phenoxycarbonyl)hydroxylamine (IX) by means of PPh3 and DEAD in THF affords the protected carbamate derivative (X), which is finally treated with ammonia in methanol.