Conversion of velutinal esters in the fruit bodies of Russula cuprea

The only sesquiterpenoid present in intact fruit bodies of Russula cuprea was found to be velutinal, as a mixture of stearic, oleic, linoleic and palmitic acid esters. As a response to injury, the velutinal esters are converted to the marasmane sesquiterpenes isovelleral, isovellerol, isovellerdiol and the new aldehyde cupreal [(2S, 3R, 6R, 7S, 8S, 9R)-8,13- dihydroxy-5-oxo-marasmane]. The structure of cupreal was determined by a combination of spectroscopic and computational methods.