diastereomereic acetals((-)-9and(+)-10 or(+)-9 and(-)-10)with the title vicinal-diol(+)-or ( )-5), affording opticallypure (R)-( )-3. The resolving agents (( + )- and ( )-5) were readily synthesized from unnatural(2S,3S)-(-)-tartaric acid((-)-6)or D-(-)-mannitol and natural (2R,3R)-(+)-tartaric acid((+)6), respectively. The undesired enantiomer ((S)-(+ )-3) obtained by the optical resolution could be racemized