Alkenenitriles: conjugate additions of alkyl iodides with a silica-supported zinc-copper matrix in water.

A new silica-supported zinc-copper matrix reagent promotes the conjugate addition of alkyl iodides to cyclic and acyclic alkenenitriles in water. X-ray diffraction and electron microscopy techniques suggest that the active copper species generated from elemental zinc and copper(I) iodide is finely dispersed, zerovalent copper. Alkyl iodides react with the silica-supported reagent to generate putative radicaloid intermediates that efficiently add to alkenenitriles to provide beta-substituted nitriles. Conjugate additions to acyclic and cyclic 5-7-membered alkenenitriles are most effective for primary alkyliodides, although secondary and tertiary alkyliodides are viable reaction partners. The strategy addresses the challenge of performing conjugate additions to disubstituted alkenenitriles and demonstrates the beneficial role of the silica-supported reagent.