Haiyong Yu, Zhi-Xiang Yu
We hypothesized that the cyclobutenes in 1H-cyclobuta[de]naphthalenes (CBNs) could have high strains and can take part in cycloadditions. This was proven by experiments showing that, under Rh catalysis, CBNs and CO can achieve (4 + 1) cycloaddition. Quantum chemical calculations have been utilized to analyze the detailed reaction mechanism and regiochemistry of this (4 + 1) reaction.