Lewis Acid Catalyzed Reactions of Donor-Acceptor Cyclopropanes with Anthracenes

The reactions of 2-aryl-1,1-cyclopropane diesters with anthracene derivatives were studied for the first time. Three kinds of reaction products are formed depending on the nature of the aryl group and the substituents in the anthracene. The first one is the product of [4+3] cycloaddition of cyclopropane to a diene moiety of anthracene. The second one also has a seven-membered ring and is formed by the Lewis acid catalyzed electrophihc attack of cyclopropane onto the C9 atom of anthracene followed by intramolecular attack of the formed arenonium ion on aryl group of the starting cyclopropane. Lastly, the common Friedel-Crafts products are formed. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)