合成路线1

Chiral 5-oxohexanoic ester intermediate (XI): The reaction of 3-hydroxy-2(S)-methylpropionic acid methyl ester (I) with benzyl trichloroacetimidate gives the benzyl ether (II), which is condensed with ethylmagnesium bromide in THF to yield the chiral ketone (III). The reaction of (III) with (c-hexyl)2B-Cl ad TEA affords the boron enolate (IV), which is condensed with acetaldehyde to provide the intermediate boron aldolate (V). The reduction of (V) with LiBH4 and H2O2 in aqueous methanol gives the chiral diol (VI), which is silylated by means of Tbdms-OTf to yield the bis-silyl ether (VII). The selective deprotection of (VII) by means of CSA in methanol/dichloromethane affords the alcohol (VIII), which is debenzylated by means of H2 over Pd/C in ethanol to provide the diol (IX). The oxidation of (IX) with (COCl)2 and DMSO in dichloromethane gives the intermediate oxoaldehyde that is oxidized with NaClO2 to yield the 5-oxohexanoic acid (X). Finally, this compound is methylated with diazomethane in ethyl ether to afford the target, chiral 5-oxohexanoic ester intermediate (XI).