合成路线1

The demethylation of 1-methyl-1,2,5,6-tetrahydropyridine-3-carboxylic acid methyl ester (I) by reaction with 1-chloroethyl chloroformate, followed by reaction with Boc2O gives 1-(tert-butoxycarbonyl) -1,2,5,6-tetrahydropyridine-3-carboxylic acid methyl ester (II). The isomerization of (II) by means of LDA in THF yields 1-(tert-butoxycarbonyl) -1,2,3,6-tetrahydropyridine-3-carboxylic acid methyl ester (III), which is reduced with LiBHEt3 in THF to afford the hydroxymethyl derivative (IV). The reaction of (IV) with MCPBA in dichloromethane provides the epoxide (V), which is treated with refluxing aq. KOH, resulting in a racemic mixture of the enantiomers (VI) and (VII) as the major products. Finally, the target isofagomine is separated by chiral chromatography.