(+)-Sclareolide has been synthesised from (+)-sclareol oxide
in one step in high yield, by treatment with peroxy acids under very
mild conditions. The reaction pathway does not follow the usual
oxidative cleavage of the double bond of (+)-sclareol oxide,
but the key intermediate is a five-membered ring hemiketal. The
direct conversion of a six-membered cyclic enol ether into a γ-lactone
is described for the first time.
cyclic enol ethers - γ-lactones - ring
contraction - oxidative rearrangement - peroxy acids
