Intramolecular Diels-Alder Additions. 2. Photochemical and Wagner-Meerwein Rearrangements of 9,12-Bridged Ethenoanthracenes

Article abstract of DOI:10.1021/jo01296a032

The direct photolysis of 9,12-bridged ethenoanthracenes, readily accessible by intermolecular Diels-Alder reaction of suitably 9-substituted anthracenes, gives fused dibenzocyclooctatetraenes of type 2.Sensitized photolysis produces mixtures of the two isomeric dibenzosemibullvalenes, e.g., 12 and 13.Acid-catalyzed Wagner-Meerwein rearrangements of benzenobenzisoindoles of types 22 and 25 followed by reduction leads to trans- and cis-tetrahydromethanodibenzocycloheptapyrroles 27 and 28.