Lewis Acid Catalyzed Reactions of Donor–Acceptor Cyclopropanes with Anthracenes

Abstract

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 electrophilic 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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Lewis Acid‐Catalyzed [3+4] Annulation of 2‐(Heteroaryl)‐ cyclopropane‐1,1‐dicarboxylates with Cyclopentadiene

“…In this case the DA cyclopropane enters the annulation reaction as a synthetic equivalent to 1,3‐zwitterionic synthon of type B . Such a reactivity was observed for cyclopropanes with electron‐enriched aromatic substituents 6b,7,8…”

Carbocycles from donor–acceptor cyclopropanes

“…In the same year, Ivanova published work reporting the reaction of anthracene 193 with cyclopropanes 194 to access carbocycle 195 (Scheme 48B). 61 Unlike the previous report, this work was very selective toward cyclopropane substitution and thus only a small scope was achieved with low to moderate yields. In a similar manner, Marino next explored the tandem process with alkoxy activated cyclopropanes 200 and triphenylphosphonium alkenes 201 to give the corresponding fused bicyclic system 202 (Scheme 50A).…”

Lewis‐Acid‐Catalysed Friedel–Crafts Alk­ylation of Donor–Acceptor Cyclopropanes with Electron‐Rich Benzenes to Generate 1,1‐Diarylalkanes

“…However, the use of electron‐rich aromatic compounds, including N , N ‐dialkylanilines, in the Friedel–Crafts alkylation of D–A cyclopropanes has rarely been reported. Moreover, to date, only one example of the Friedel–Crafts alkylation of 2‐phenyl‐1,1‐cyclopropane diester with 1,3‐dimethoxybenzene has been reported 9. In this paper, we report the first successful intermolecular Friedel–Crafts alkylation of D–A cyclopropanes with electron‐rich aromatic compounds, including N , N ‐dialkylanilines, to give 1,1‐diarylalkanes.…”