A novel and stereoselective synthesis of 2-bromo-6-chloro-5-methylcyclohex-4-ene-1,3-diyl diacetate: conduritol-A derivative

Abstract

The stereoselective synthesis of 2-bromo-6-chloro-5-methylcyclohex-4-ene-1,3-diyl diacetate, methyl-substituted dihaloconduritol-A is reported. Bromination of 2-methylbenzo-1,4-quinone followed by the reduction in the carbonyl groups with NaBH4 to give a dioldibromo compound. The diol was converted to diacetates by acetylation with Ac2O-pyridine. Reaction of methyl-dioldibromodiacetate with LiOH gave stereoselectively the monoepoxide compound. Controlled reaction of the epoxide with AcCl in methylene chloride furnished the desired new dihaloconduritol-A derivative which was characterized by spectroscopic methods. All the synthesized compounds were characterized by FT-IR, H-1-NMR, C-13-NMR, COSY (2D-NMR), and HRMS analyses.