An entry to 4-aryl-azetidinones via alkylation of nucleophilic arenes using four-membered acyliminium cations

The acyliminium cations derived from 4-acyloxy-azetidinones in the presence of Lewis acids can be used to alkylate nucleophilic arenes in both the inter- and intramolecular processes. The former reactions were successfully carried out with p-dimethoxy-benzene in moderate yield, whereas the latter reactions can be done with a variety of nucleophilic arenes in a good yield.