Synthesis of Cyclobutane-Fused Oxygen-Containing Tricyclic Framework via Thermally-Promoted Intramolecular Cycloaddition of Cyclohexadienone-Tethered Allenes

We have developed a unique approach for the thermally-promoted cycloaddition of cyclohexadienone-tethered allenes to form versatile cyclobutane-fused oxygen containing tricyclic framework in an environmentally friendly and atomic economic fashion in high regioselectivity. The reaction encompasses a broad substrate scope and functional group tolerance of cyclohexadienone moieties. Moreover, the cycloaddition was also applicable to the late-stage functionalization of pharmaceutically relevant compounds.