The D iels‐ A lder Reaction with Maleic Anhydride*Present address, University of Southern California, Los Angeles, California.

Abstract The Diels‐Alder reaction consists in an addition of a compound containing a double or triple bond (usually activated by additional unsaturation in the alpha, beta‐position) to the 1,4‐positions of a conjugated dienes system with the formation of a six‐membered ring, Various dienes systems to dienophiles are described as typical examples of the Diels‐Alder reaction. A noteworthy feature of this reaction is the great variety of compounds that may serve as the dienophile. Among the most widely employed dienophiles are maleic anhydride and closely related dicarboxylic acid derivatives.