Intramolecular hydrogen transfer reaction: menthon from isopulegol.
The flavor menthon (isomeric mixture of (-)-menthon and (+)-isomenthon) was obtained in good yields and selectivities by a solventless ruthenium catalyzed isomerization of the homoallylic alcohol (-)-isopulegol. In contrast to most previous assumptions on such "isomerization" reactions, this reaction follows an intermolecular pathway, with menthol and pulegon being the central intermediates in this transformation.
BASF SE, Synthesis and Homogeneous Catalysis (GCS), 67056 Ludwigshafen, Germany.
Thomas
T
Schaub
Stefan
S
Rüdenauer
Martine
M
Weis