the interaction of aryl diazonium halides with unsaturated compounds, yielding products formed by the combination of an aryl radical and a halogen atom along the multiple bond. The products often lose a hydrogen halide during the reaction process:
Alpha- and beta-unsaturated aldehydes, ketones and carboxylic acids, vinyl ethers, styrene, and other compounds characterized by a double bond, as well as acetylene, may be introduced into the Meerwein reaction, which is catalyzed by Cu+ or Cu+ + salts. The Meerwein reaction is used in organic synthesis under laboratory conditions. It was discovered in 1939 by the German chemist H. Meerwein.