ABSTRACT
A cycloaddition reaction involves two or more unsaturated molecules (or parts of the same molecule) combining with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity. When the unsaturated molecules consist of a conjugated diene and a species containing a carbon-carbon double or triple bond (termed a dienophile) the cycloaddition is referred to as a Diels-Alder reaction. The reaction is synthetically important because two new sigma bonds, a six-membered ring, and up to four stereocenters are formed in a single step.
