The Construction of X-CN (X= N, S, O) Bonds

The cyano moiety is a common and important functional group that exists in a myriad of medicinal molecules and natural products. Moreover, nitriles serve as versatile precursors that can readily be converted into diverse functional groups as well as the nitrogen-containing cyclic molecules. As a result, cyanation has become a significant type of transformation in organic chemistry. However, in comparison with the well-developed C-cyanation, few works have been reported dealing with the N-, S-and O-cyanation processes. Apart from the classical von Braun reaction, chemists have developed a number of methods with various cyanating reagents to achieve such X-cyanations (X=N, S, O). In this review, recent advances (especially those after 2000) in the X-CN (X=N, S, O) bond formation are summarized with discussion and the outlooks are also listed.