SYNTHESIS OF ENANTIOMERICALLY PURE SUBSTITUTED CYCLOPENTENES FROM (-)-QUINIC ACID

The synthesis of a large variety of enantiomerically pure substituted reactive cyclopentenes 16, 23, 24 and 28 have been synthesized from the readily available (−)-quinic acid 1. The straightforward strategy involves a high-yielding intramolecular aldolization-dehydration of acyclic 1,6-dialdehydes 13, 18, 19 and 27 obtained by oxidative cleavage of cyclohexanediols 5, 7, 11 and 12, using either lead tetraacetate or triphenylbismuth carbonate. Neither sulfoxide formation nor racemization of the intermediate dialdehydes at the oxygenated chiral centre was observed. Transformation of the thioacetal 25 to the corresponding ketone 26 using phenylselenic anhydride is also described.