Experimental proof that the Diels-Alder reaction of tetracyanoethylene with 9,10-dimethylanthracene passes through formation of a complex between the reactants

Abstract

Up to the present, it has been considered impossible to determine kinetically whether the complex often formed between diene and dienophile is a true intermediate in the Diels-Alder reaction. A method based on the effect of temperature on the reaction rates has been tested and found successful in proving that the complex formed by tetracyanoethylene and 9,10-dimethylanthracene is indeed a true intermediate in the Diels-Alder reaction of those molecules.