合成路线1

Acylation of the chiral oxazolidinone (I) with undecanoyl chloride furnished the N-acyl oxazolidinone (II). The lithium enolate of (II) was diastereoselectively alkylated with tert-butyl bromoacetate (III) producing (IV) as the major isomer. Then, removal of the chiral auxiliary of (IV) with lithium benzyloxide yielded benzyl ester (V). Acidic cleavage of the tert-butyl ester group of (V) provided carboxylic acid (VI), which was subsequently converted to the trichloroethyl ester (VII) via formation of the corresponding acid chloride, followed by treatment with trichloroethanol. After removal of the benzyl ester group of (VII) by hydrogenolysis, chlorination by means of oxalyl chloride gave acid chloride (VIII). This was then coupled with the protected (S)-perhydropyrazine-3-carboxylic acid (IX) to afford amide (X).