Friedel–Crafts Alkylation of Aromatics by TiCl4-Promoted Ring Cleavage of 3-Arylcyclobutanones

Abstract

Ring cleavage of 3-arylcyclobutanones and successive Friedel–Crafts alkylation of methoxy- or alkyl-substituted benzene derivatives proceeded to give 3,3-diarylbutan-2-ones by activation with titanium tetrachloride.

Brønsted Acid-Catalyzed Cascade Ring-Opening/Cyclization of 3-Ethoxy Cyclobutanones to Access 2,8-Dioxabicyclo[3.3.1]nonane Derivatives

“…After the successful substrate scope evaluation, we conducted some control experiments to gain insight into the reaction mechanism. First, 3-ethoxy cyclobutanone 1a was reacted with 1,3,5-trimethoxy benzene and 4-methoxy phenol separately under the optimal reaction condition, but no such double addition products 13 or even simple Friedel−Crafts arylated products 14 were obtained (Scheme 4a). In addition, when trimethoxy benzene was employed along with 2-naphthol 2a and cyclobutanone 1a, only naphthol-containing product 3aa was produced.…”