合成路线1

The new intermediates, the oxazolidinone (XX) and the aldehyde (XXI), are obtained as follows: Oxazolidinone (XX): The ring opening of cyclohexane epoxide (XXVI) with methanol and CSA followed by silylation with tert-butyldimethylsilyl trifluoromethanesulfonate in dichloromethane gives compound (XXVII), which is debenzylated by hydrogenolysis and oxidized with oxalyl chloride to the cyclohexanone (XXVIII). Dehydrogenation of (XXVIII) by treatment with lithium diiosopropylamide (LDA), tosyl chloride and palladium diacetate yields the cyclohexenone (XXIX), which is reduced with LiBH4 - CeCl3 in methanol/THF to the cyclohexenol (XXX). The condensation of (XXX) with dimethylacetamide diethylacetal (XXXI) in refluxing xylene affords the cyclohexylacetamide (XXXII), which is reduced with lithium triethylborohydride in THF and with H2 over Pd/C in ethanol to give the cyclohexylethanol (XXXIII). The dehydration of (XXXIII) through a selenium derivative yields the vinyl compound (XXXIV), which is oxidized with ozone to the aldehyde (XXXV). Finally, the condensation of (XXXV) with the phosphonate (XXXVI) by means of IEN and LiCl in acetonitrile followed by a desilylation with HF and silylation with tert-butyldiphenylsilyl chloride in DMF yields the oxazolidinone (XX) (see K.C. Nicolau et al., J Chem Soc Chem Commun 1993, 7: 619). (1,2)