A 2-STEP ASYMMETRIC-SYNTHESIS OF (R)-MONOARYL EPOXIDES USING A CHIRAL OXATHIANE AS A RECOVERABLE REAGENT - APPLICATION TO THE PREPARATION OF (R)-BETA-ADRENERGIC COMPOUNDS

It is shown that chiral oxathiane 1 is a recoverable and efficient chiral auxiliary which provides, in two steps, (R)-monoaryl epoxides in high enantiomeric purity (98% R and 92% R according to the solvent used). (R)-beta-Adrenergic compounds (R)-(-)-DCI and (R)-(-)-pronethalol call then be obtained from a regioselective opening of the corresponding epoxides using the reagent LiAl(NHR)(4)/NH(2)R.