A simple and efficient synthesis of enantiomeric (3aRS,4RS,6aSR)-4-hydroxy-3,3a,4,6a-tetrahydro-1H-cyclopenta[c]furan-1-ones

Diastereomeric amides produced via the cleavage of easily available (±)-7,7-dichloro-4-exo-trimethylsilylbicyclo[3.2.0]hept-2-en-6-one by treatment with (+)-α-methylbenzylamine were transformed into bicyclic lactam-aminals, which can easily be separated by column chromatography on SiO2. The latter products lead to enantiomeric (3a,6a)-4-hydroxy-3,3a,4,6a-tetrahydro-1H-cyclopenta[c]furan-1-ones after the removal of the chiral auxiliary and epoxidation.