The thermal isomerization of the sesquiterpenes isovelleral and merulidial. A reversible ring opening of the cis-methylcyclopropanecarboxaldehyde group via an …
Fungal sesquiterpene dialdehydea of marasmane and isolactarane types, such as isovelleral (1) and meddial (P), undergo a reversible thermal rearrangement to products (eg, 2 and 8) with inverted orientations of the cyclopropane rings. The process is shown to involve an intramolecular ene reaction with a bicyclic enol intermediate 13 which was trapped as an E-silyl ether 17. In the presence of D20, deuterium ie incorporated ...
