Atom-Economical and Metal-Free Synthesis of Multisubstituted Furans from Intramolecular Aziridine Ring Opening

Multisubstituted furans were prepared from dialkyl 2-(aziridin-2-ylmethylene)­malonate and/or 1,3-dione through aziridine ring opening by the internal carbonyl oxygen with the assistance of BF₃·OEt₂, followed by aromatization. This synthetic method is free from any metal and is atom-economical with all of the atoms in the starting material retained in the final product.