合成路线图解说明: Acylation of Evans oxazolidinone (II) with heptanoyl chloride (I) provides the chiral adduct (III). The lithium enolate of (III) is then diastereoselectively alkylated with tert-butyl bromoacetate (IV) to afford the succinate derivative (V). Removal of the chiral auxiliary group of (V) with lithium peroxide furnishes the carboxylic acid (VI), which is further activated as the succinimidyl ester (VII) upon treatment with N-hydroxysuccinimide and DCC. The activated ester (VII) is then condensed with L-valine (VIII), producing amide (IX). Subsequent coupling of (IX) with N-aminoproline methyl ester (X) leads to hydrazide (XI). After acidic tert-butyl ester cleavage in (XI), the resultant carboxylic acid (XII) is condensed with hydroxylamine to yield the desired hydroxamic acid. |