A general method is described for effecting the intramolecular Diels-Alder reaction of the furan diene in which the side arm connecting the diene to the dienophile contains four carbon atoms. The use of 1.1 equivalents of methylaluminum dichloride at-78° C for 2-8 h shifts the Diels-Alder equilibrium towards the products and provides the oxatricyclo adducts in good to excellent yield. Catalytic quantities of methylaluminum dichloride (10 mol%) ...
