Copper-catalyzed oxycyanation of conjugated dienes: A comparison with the diacetoxylation reaction

Copper bromide-based catalysts promote the formation of 1,4-dicyano-2-butene from butadiene in acetonitrile as solvent. In other solvents such as pyridine or dimethyl sulfoxide, the reaction follows another pathway and 2-cyanopyridine is produced in small yield. These reactions can be applied to other conjugated dienes such as isoprene or 1,3-pentadiene, but the yields are lower than with butadiene. In fact, the described catalyst is poorly active and the yields are moderate to low according to the reactant. The results are discussed in relation to other copper bromide-based catalytic reactions (hydrocyanation, hydroacetoxylation, and diacetoxylation reactions). © 1989.