In organic chemistry, an acyl cyanide is a functional group with the formula R−C(O)CN and structure R−C(=O)−C≡N. It consists of an acyl group (R−C=O) attached to cyanide (−C≡N). Examples include acetyl cyanide, formyl cyanide, and oxalyl dicyanide. Acyl cyanides are reagents in organic synthesis.[1][2]
Classically acyl cyanides are produced by the salt metathesis reaction of acyl chlorides with sodium cyanide:
Alternatively, they can be produced by dehydration of acyl aldoximes:
Acetyl cyanide is also prepared by hydrocyanation of ketene:
They are mild acylating agents.[2] With aqueous base, acyl cyanides break down to cyanide and the carboxylate:[3]
With azides, acyl cyanides undergo the click reaction to give acyl tetrazoles.[4]