合成路线1

The intermediate (XV) has been obtained as follows: The reaction of methyl 3-hydroxy-2(S)-methylpropionate (I) with 4-methoxybenzyl trichloroacetimidate gives methyl 3-(4-methoxybenzyloxy)-2(S)-methylpropionate (II), which is reduced with LiAlH4, yielding the primary alcohol (III). The Swern oxidation of (III) affords the aldehyde (IV), which is condensed with the chiral imidazolidinone (V) to provide the adduct (VI). The transamidation of (VI) with N,O-dimethylhydroxylamine by means of Me3Al gives the methoxyamide (VII), which is debenzylated with DDQ to yield the diol (VIII). The reaction of (VIII) with 4-methoxybenzaldehyde diethylacetal (IX) and CSA affords the cyclic ketal (X), which is condensed with the propionyloxazolidinone (XI) by means of dibutylboron triflate to furnish the adduct (XII). The silylation of the OH group of (XII) with Tbdms-OTf gives the silyl ether (XIII), which is reduced at the amide group with LiBH4 to yield the primary alcohol (XIV). Finally, this compound is treated with I2 and PPH3 to afford the intermediate iodo derivative (XV).