合成路线1

The reaction of 3-fluoroaniline (I) with isobutyl chloroformate (II) by means of K2CO3 in dichloromethane/water gives the carbamate (III), which is brominated with 1,3-dibromo-5,5-dimethylhydantoin (DBDH) to yield the 4-bromo-3-fluorophenyl carbamate (IV). The condensation of (IV) with tetrahydrothiopyran-4-one (V) by means of EtMgBr and BuLi in THF affords the tertiary alcohol (VI), which is dehydroxylated by means of poly(methylhydrosiloxane) (PMHS), (Me3Si)2O and Ts-OH in toluene to provide the intermediate (VII). The stereoselective oxidation of (VII) to the trans sulfoxide (VIII) is performed by means of Ti(OiPr)4 and tert-butyl hydroperoxide in the presence of diisopropyl D-tartrate. The cyclization of the carbamate (VIII) with (S)-3-chloropropane-1,2-diol (IX) by means of Li t-amylate in DMF gives the oxazolidinone (X), whose free OH group is activated with 3-nitrobenzenesulfonyl chloride and TEA in dichloromethane to yield the sulfonate (XII). The reaction of (XII) with NH4OH in methanol/acetonitrile affords the aminomethyl derivative (XIII), which is finally acylated with propionic anhydride (XIV) to provide the target sulfoxide.