Feller K.; Svetozarskii S.; Samitov Y.; Zil'berman E.; Razuvaev G.
(1968)
Treatment of cycloheptanone or 2-cycloheptylidenecycloheptanone with concentrated sulfuric acid, leads to self-condensation accompanied by intramolecular rearrangement and cyclization to give substituted tetrahydrofurans, ...