TheKolbe nitrile synthesis, named forHermann Kolbe, is a method for the preparation of alkylnitriles by reaction of the correspondingalkyl halide with a metalcyanide.^[1] A side product for this reaction is the formation of anisonitrile because the cyanide ion is anambident nucleophile.$${\displaystyle \underset{\text{alkyl}\text{halide}}{\text{R}-\text{X}}+\underset{\text{cyanide}\text{ion}}{{\text{CN}}^{\ominus }}⟶\underset{\text{alkyl}\text{nitrile}}{\text{R}-\text{C}\equiv \text{N}}+\underset{\text{alkyl}\text{isonitrile}}{\text{R}-\stackrel{\oplus }{\text{N}}\equiv {\text{C}}^{\ominus }}}$$ The ratio of productisomers depends on thesolvent and thereaction mechanism, and can be roughly predicted byKornblum's rule. Conditions conducive to free cyanide ions (alkali counterion,polar aprotic solvents) tend to give nitriles, whereascyanometalate andhydrogen cyanide intermediates generally react to form isonitriles.^[2]

The reaction occurs particularly well indimethyl sulfoxide (DMSO) solvent,^[3] as DMSO enables harsher conditions for cyanidation ofsterically hindered electrophiles (secondary and neopentyl halides) without rearrangement side-reactions.^{[dubious –discuss][citation needed]}

• Rosenmund–von Braun reaction, a similar reaction for the synthesis of aromatic nitriles
• Hydrocyanation § With unsaturated carbonyl compounds, a similar reaction with enones

• Substitution reactions
• Name reactions

• All accuracy disputes
• Articles with disputed statements from October 2025
• All articles with unsourced statements
• Articles with unsourced statements from March 2024