合成路线1

The intermediate (R)-formyl amide (IX) was synthesized as follows. Acylation of the lithium anion of (S)-4-benzyl-2-oxazolidinone (I) with valeryl chloride (II) provided acyl oxazolidinone (III). Subsequent diastereoselective benzyloxymethylation of (III) with chloride (IV) and TiCl4 gave benzyl ether (V). Hydrolysis of (V) with lithium peroxide, followed by coupling of the resulting carboxylic acid (VI) with diethylamine in the presence of TBTU yielded diethylamide (VII). Hydrogenolysis of the benzyl group of (VII) using Pearlman's catalyst afforded alcohol (VIII), which was oxidized to aldehyde (IX) by means of Dess-Martin periodinane or NaOCl in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) to give (IX).