Construction of [2,5]-Furanophanes by Carbene-Mediated Alkynyl Migration Cyclization

Heterophanes are widely found in natural products and drug molecules. Herein, an efficient method for the construction of [2,5]-furanophanes with different ring types and ring sizes was developed. This method is carried out with furan-free precursor through intramolecular carbene-mediated alkynyl migration and tandem cyclization strategy. In addition, a series of tetrafuran structures can be obtained by oxidative coupling of the products.