Acid-Catalyzed Intramolecular [2+2] Cycloaddition of Ene-allenones: Facile Access to Bicyclo[n.2.0] Frameworks

摘要

The fused cyclobutane fragment is a key motif found in many biologically important natural products, such as sterpurene and illudene derivatives. Among the strategies, the [2+2]-cycloaddition reaction stands out as one of the most versatile methods for the construction of such fused systems. A noteworthy class of this reaction is the intramolecular version, involving an allene and an alkene in a single molecule, which enables the stereocontrolled construction of complex poly-cyclic compounds containing methylenecyclobutane frameworks.