Hydrogen cyanide is an abundantly available feedstock that is useful for the synthesis of organonitrile intermediates, which serve as precursors for amines, amides, isocyanates, carboxylic acid, and esters. Many of these compounds are used in the manufacture of polymers, agrichemicals, cosmetics, and pharmaceuticals. Hydrogen cyanide itself is relatively unreactive, but in the presence of a catalyst HCN adds to carbonyl compounds, alkenes, and alkynes offering a direct and economical way to such organonitrile intermediates.
This chapter focuses primarily on the metal-catalyzed hydrocyanation of alkenes or alkynes. Acetone cyanohydrin and trimethylsilyl cyanide (TMSCN), both commercially available reagents, can be used for the in-situ generation of HCN. In some transition-metal catalyzed additions, TMSCN acts as a surrogate for HCN, giving products where the TMS group replaces the hydrogen. Preparatively, these reagents provide some advantages since the handling of toxic HCN is avoided. Reactions of these reagents are included here under appropriate substrate and direct comparison of yield and selectivity can be made.