Thec yano moiety is ac ommon and important functional group that exists in am yriado fm edicinal molecules and natural products.M oreover, nitriles serve as versatilep recursors that can readily be converted into diverse functional groups as well as the nitrogen-containing cyclic molecules.A s ar esult, cyanation has become as ignificant type of transformation in organic chemistry.H owever, in comparison with the well-developed C-cyanation, few works have been reported dealing with the N-, S-and O-cyanation processes.A part from the classical von Braun reaction, chemists have developed an umber of methods with various cyanating reagents to achieve such X-cyanations (X = N, S, O). In this review,r ecent advances( especially those after 2000) in the X-CN (X = N, S, O) bondf ormation are summarized with discussion andt he outlooksa re also listed.1I ntroduction 2F ormation of the N-CN Bond 2.Scheme 23. Iodine(III)-promted cleavage of C-S bonds leading to thiocyanates.Scheme 24. Tr aditional methods for constructing the O-CN bond.

An unprecedented approach to N-trifluoromethylations of electron-rich nucleophilic sites following a radical pathway is reported. Accordingly, various sulfoximines (19 examples) have been N-trifluoromethylated, providing previously unreported products with satisfying functionality tolerance in moderate to good yields. With a C-N bond length at the N-CF3 moiety of 1.341 Å the respective linkage is shorter than a traditional C-N single bond and comparable with that of a C-N double bond.

The copper-catalyzed cyanation of disulfides by azobisisobutyronitrile (AIBN) was developed, leading to thiocyanates in moderate to good yields. This procedure tolerates a series of functional groups, such as chloro, nitro, methyl and methoxycarbonyl in the phenyl ring of disulfides. Notably, it enables the use of two ArS units in (ArS)2. CuI was found to be essential for the in situ formation of cyanide anions.