First enantioselective syntheses of (+)- and (-)-wilforonide by using chiral auxiliaries derived from the same chiral source.

[see structure]. The first enantioselective syntheses of both (+)-wilforonide (>98% ee) and (-)-wilforonide (>98% ee) have been accomplished by employing chiral auxiliaries derived from the same chiral source, (R)-pulegone. The bicyclic skeleton of wilforonide was constructed by using Mn(III)-based oxidative radical cyclization reactions of chiral beta-keto esters. The absolute configuration of natural wilforonide has been established to be (5aR,9aR).