Metal-Free Hyperbaric Multicomponent Approach to 4-Aryl[2.2]Paracyclophanes

Herein, we report the first metal-free synthesis of 4-aryl[2.2]paracyclophanes, an important scaffold in organic ligands and material science panorama. In order to avoid the use of toxic and expensive metal catalyst, a multicomponent hyperbaric protocol has been envisaged. First, easy-to-synthesize paracyclophane-substituted butenones underwent acid-catalyzed enol acetylation in the presence of isopropenyl acetate to generate in situ acetoxy-diene intermediates, which were then reacted with methyl propiolate in a hyperbaric regioselective Diels-Alder reaction. Oxidation of the resulting cycloadducts delivered the expected products showing the potential for further functionalization.