合成路线1

Synthesis of oxazolidine intermediate (XVI): The reaction of dimethyl L-tartrate (I) with benzaldehyde and Ts-OH gives the benzylidene ketal (II), which is reduced with LiAlH4/AlCl3 to yield the monobenzylated tetrol (III). The reaction of (III) with 2,2-dimethoxypropane (IV) and TsOH affords the acetonide (V), which is protected at the primary OH group with Mpm-Cl and NaH to provide the corresponding ether (VI). The debenzylation of (VI) with H2 over Raney-Ni in ethanol, followed by reaction with MsCl and TEA in dichloromethane, gives the mesylate (VII), which is treated with HCl in methanol to yield the diol (VIII). The reaction of (VIII) with K2CO3 in methanol affords the epoxide (IX), which is opened with NaN3 in refluxing ethanol to provide the azide (X). The selective monosilylation of (X) with Tbdps-Cl, TEA and DMAP in dichloromethane furnishes the silyl ether (XI). The reduction of the azido group of (XI) with PPh3 in THF/water gives the amine (XII), which is protected with Troc-Cl and NaHCO3 to afford the carbamate (XIII). The reaction of (XIII) with 2,2-dimethoxypropane (IV) and TsOH provides the oxazolidine (XIV), which is selectively deprotected at the Mpm group with DDQ in dichloromethane, giving the primary alcohol (XV). Finally, this compound is esterified with Tf2O and TEA in CH2Cl2 to obtain the desired oxazolidine intermediate (XVI).