Natually accuring bicycle terpene prepn

摘要

A naturally occurring bicyclic ketone (noot Ratone) of general formula: is prepd. by the oxidation of valencene and then either (a) dehydration directly to the bicyclic ketone, or (b) reduction to the carbinol followed by oxidation to the bicyclic ketone. A dehydration agent e.g. a strong inorganic base (NaOH or KOH) may be used in step (a). For the oxidation step, a catalyst e.g. of Cr or Mg may be used with the oxygen; alternatively, a free-radical initiator may be present. The bicyclic ketones are useful in the manufacture of synthetic grape-fruit aromas.