SHYNTHESIS OF (1S,5R)-KARAHANA ETHER AND (1S,5R)-KARAHANA LACTONE. THE OPTICALLY ACTIVE FORMS OF UNIQUE MONOTERPENES WITH A 6-OXABICYCLOOCTANE RING SYSTEM

Article abstract of DOI:10.1016/S0040-4020(01)91348-1

(1S,5R)-(-)-Karahana ether (8,8-dimethyl-2-methylene-6-oxabicyclo<3.2.1>octane) and (1S,5R)-(-)-karahana lactone (8,8-dimethyl-2-methylene-6-oxabicyclo<3.2.1>octan-7-one) were synthesized from (S)-3-hydroxy-2,2-dimethylcyclohexanone.The natural karahana lactone was shown to be almost racemic (ca. 1.3 percent e.e.).