Cyclopentanoids from phenol. VIII. Enantioconvergent routes to chiral prostanoid intermediates

Abstract

Inversion of alcohol configurations in hydroxycyclopentenone and cyclopentenol intermediates prepared from the (1S,4S)-3.5,5-trichloro-1,4-dihydroxycyclopent-2-ene-1-carboxylic acid (2) leads to the same 2-substituted (4R)-4-hydroxycyclopent-2-enone derivatives of type (3) as have previously been synthesized from the enantiomeric (1R,4R) acid (1). Similarly, the (1R,4R) acid (1) can be converted into (R)-4-hydroxycyclopent-2-enone (5), previously obtained from the enantiomeric (1S,4S) acid (2). The cyclopentenones (3) and (5), which are important chiral intermediates in prostanoid synthesis, are thus available from phenol by enantioconvergent routes.