Copper-Catalyzed Cyanation of Aryl- and Alkenylboronic Reagents with Cyanogen Iodide

Abstract

Direct catalytic cyanation of organoboronic acids with cyanogen iodide has been achieved by using a copper-bipyridine catalyst system. The cyanation reaction is likely to occur through two catalytic cycles: copper(II)-catalyzed iodination of organoboronic acids and the following cyanidocopper(I)-mediated cyanation of organic iodides.

Copper Mediated Chemo‐ and Stereoselective Cyanation Reactions

“…The catalytic reaction proceeded by the iodination of the organoboronic acid followed by the cyanation of organic iodides with high yields and good substrate tolerance (See Figure 23). [34] Copper acetate was an excellent catalytic material for the anti-selective iodocyanation and dicyanation of a broad range of substituted internal alkynes. IÀ CN was used as the iodocynation source, and ethanol was used as a solvent.Mechanistic studies reveal the stepwise iodide formation followed by selective monocynation (See Figure 24).…”

“…The catalytic reaction proceeded by the iodination of the organoboronic acid followed by the cyanation of organic iodides with high yields and good substrate tolerance (See Figure 23). [34] …”

Copper-Catalyzed Regio- and Stereoselective Iodocyanation and Dicyanation of Alkynes with Cyanogen Iodide

“…Cyanogen bromide serves as an electrophilic cyanation reagent and is effectively activated in the presence of Lewis acidic metals such as GaCl 3 (Scheme , eq 2). , By contrast, cyanogen iodide does not work well as an electrophilic cyanation agent but can be used in combination with a copper catalyst. We have found that a copper catalyst was effective for the reaction of cyanogen iodide with alkynes giving alkynyl cyanides, and that the alkynyl cyanides were obtained through the formation of alkynyl iodides as an intermediate (Scheme , eq 3) . In this contribution, we report a copper-catalyzed anti -selective iodocyanation and dicyanation of alkynes using cyanogen iodide, in which the two reactions were switched simply by changing the reaction conditions (Scheme , eq 4). , …”

Synthesis of Cyanamides via a One-Pot Oxidation–Cyanation of Primary and Secondary Amines

“…Cyanogen halides, such as cyanogen bromide (BrCN), are highly versatile reagents in organic synthesis with additional applications such as peptide mapping and nucleotide ligation . Due to the high electrophilicity of their CN-moiety, cyanogen halides are most commonly used for the cyanation of N, S, O, and C nucleophiles, with the formation of cyanamides from primary, secondary, or tertiary amines (von Braun reaction) being most prominent . The cyanamide moiety is found in selected pharmaceuticals and agrochemicals .…”