Reaction of the N-carbobenzyloxy-protected tetrahydropyridine derivative (I) with m-chloroperbenzoic acid (MCPBA) in ethylene chloride gives the stable oily epoxide (II), which, upon treatment with 2,3-dimethyphenol in acetonitrile in the presence of aqueous NaOH, affords the crystalline trans-3 hydroxy-4-phenoxy derivative (III). Oxidation of this aicohol to the corresponding ketone (IV) is best achieved by means of DMSO reagents, in particular DMSO and pyridine-SO3 adduct. Treatment of the ketone (IV) with potassium tri-sec-butylborohydride (K-Selectride(R)) in THF yields the cis-3-hydroxy-4-phenoxy derivative (V) in a highly stereoselective reaction. Hydrogenation of (V) with H2 over Pd/C in ethanol and subsequent salt formation with aqueous H2SO4 leads to racemic, diastereomerically pure CGP-l5210 G.

Reaction of the N-carbobenzyloxy-protected tetrahydropyridine derivative (I) with m-chloroperbenzoic acid (MCPBA) in ethylene chloride gives the stable oily epoxide (II), which, upon treatment with 2,3-dimethyphenol in acetonitrile in the presence of aqueous NaOH, affords the crystalline trans-3 hydroxy-4-phenoxy derivative (III). Oxidation of this aicohol to the corresponding ketone (IV) is best achieved by means of DMSO reagents, in particular DMSO and pyridine-SO3 adduct. Treatment of the ketone (IV) with potassium tri-sec-butylborohydride (K-Selectride(R)) in THF yields the cis-3-hydroxy-4-phenoxy derivative (V) in a highly stereoselective reaction. Hydrogenation of (V) with H2 over Pd/C in ethanol and subsequent salt formation with aqueous H2SO4 leads to racemic, diastereomerically pure CGP-l5210 G.

Reaction of the N-carbobenzyloxy-protected tetrahydropyridine derivative (I) with m-chloroperbenzoic acid (MCPBA) in ethylene chloride gives the stable oily epoxide (II), which, upon treatment with 2,3-dimethyphenol in acetonitrile in the presence of aqueous NaOH, affords the crystalline trans-3 hydroxy-4-phenoxy derivative (III). Oxidation of this aicohol to the corresponding ketone (IV) is best achieved by means of DMSO reagents, in particular DMSO and pyridine-SO3 adduct. Treatment of the ketone (IV) with potassium tri-sec-butylborohydride (K-Selectride(R)) in THF yields the cis-3-hydroxy-4-phenoxy derivative (V) in a highly stereoselective reaction. Hydrogenation of (V) with H2 over Pd/C in ethanol and subsequent salt formation with aqueous H2SO4 leads to racemic, diastereomerically pure CGP-l5210 G.