Thermally induced intramolecular [4 + 2] dearomative cycloaddition reaction of anthracene-tethered vinylidenecyclopropanes

Abstract

This paper reports a synthetic method for the rapid construction of dibenzobicyclo[2.2.2]octane frameworks through an intramolecular [4 + 2] dearomative cycloaddition reaction under catalyst-free conditions. Utilizing anthracene-tethered vinylidenecyclopropane derivatives (Anth-VDCPs) as substrates, the reaction proceeds under mild heating conditions, demonstrating excellent functional group tolerance and delivering the target products in moderate to excellent yields. Notably, two distinct cycloaddition products can be selectively formed by strategically varying the reaction temperature and substituent positions on the anthracene core. The large-scale synthesis and synthetic transformations of the products were also demonstrated. DFT calculations rationalized the reaction mechanism and the origin of regio-selectivity of the products.