合成路线1

The acylation of (-)-2,10-camphorsultam (II) with octanoyl chloride (I) provides the N-octanoyl sultam (III). Diastereoselective alkylation of the lithium enolate of (III) with allyl bromide (IV) gives rise to the (2S)-2-propenoyloctanoyl sultam (V). Hydrolysis of the N-acyl sultam (V) to furnish acid (VI) is then effected by treatment with hydrogen peroxide-tetrabutylammonium hydroxide. Finally, catalytic hydrogenation of the unsaturated acid (VI) in the presence of either Pd/C or Pt/C yields the required (R)-2-propyloctanoic acid. Alternatively, the title compound is obtained by hydrogenation of the N-acyl sultam (V) to the saturated derivative (VII), followed by hydrolytic removal of the camphorsultam moiety.