Ensemble of Pinanones from the Permanganate Oxidation of Myrtenal

The buffered permanganate
oxidation of (−)-myternal, a member
of the pinene family, provides the α-hydroxyketone (−)-(1R,3S,5R)-3-hydroxy-6,6-dimethylbicyclo­[3.1.1]­heptan-2-one
in preparative yield (65% on a multigram scale). This α-hydroxyketone
is oxidized, in a second reaction, to the α,β-diketone
(1R,5R)-6,6-dimethylbicyclo­[3.1.1]­heptane-2,3-dione
(“PinDione”). As both oxidations are fast, simple, safe,
inexpensive, good-yielding, and multigram scalable, these transformations
are a preparative expansion of the pinane family.