[AlCl3 + 2THF]: A New and Efficient Catalytic System for Diels−Alder Cycloaddition of α,β-Unsaturated Carbonyl Compounds under Solvent-Free Conditions

[AlCl(3) + 2THF] is a new catalytic system for the Diels-Alder cycloaddition under SFC and air atmosphere. By using equimolar amounts of reactants, this catalyst prevents the polymerization of the diene and allows the corresponding adducts to be isolated with high regio- and stereocontrol and in excellent yields. [reaction: see text]