Michael addition of 4-(phenylsulfanyl)thiophenol (II) to cyclohexenone (I) afforded the ketosulfide (III). This was reduced with NaBH4 to give a diastereomeric mixture of alcohols (IV). Subsequent oxidation of sulfide group of (IV) with Oxone provided sulfone (V). Condensation with potassium thioacetate under Mitsunobu conditions gave the corresponding thioester as a mixture of isomers, from which the major trans isomer (VI) was isolated by chromatography. Finally, deprotection of (VI) with sodium methoxide in MeOH yielded the target thiol.
Michael addition of 4-(phenoxy)thiophenol (II) to cyclohexenone (I) afforded the ketosulfide (III). This was reduced with NaBH4 to give a diastereomeric mixture of alcohols (IV). Subsequent oxidation of sulfide group of (IV) with Oxone provided sulfone (V). Condensation with potassium thioacetate under Mitsunobu conditions gave the corresponding thioester as a mixture of isomers, from which the major trans isomer (VI) was isolated by chromatography. Finally, deprotection of (VI) with sodium methoxide in MeOH yielded the target thiol.