Aerobic Copper-Promoted Radical-Type Cleavage of Coordinated Cyanide Anion: Nitrogen Transfer to Aldehydes To Form Nitriles

Abstract

We have disclosed for the first time the copper-promoted C≡N triple bond cleavage of coordinated cyanide anion under a dioxygen atmosphere, which enables a nitrogen transfer to various aldehydes. Mechanistic study of this unprecedented transformation suggests that the single electron-transfer process could be involved in the overall course. This protocol provides a new cleavage pattern for the cyanide ion and would eventually lead to a more useful synthetic pathway to nitriles from aldehydes.

Catalytic Promiscuity of Galactose Oxidase: A Mild Synthesis of Nitriles from Alcohols, Air, and Ammonia

“…General methods for the synthesis of nitriles include dehydration of amides, formal acid–nitrile exchange, Sandmeyer and Rosenmund–von Braun reactions, transition‐metal‐catalysed cyanation, electrophilic cyanide transfer, and radical‐type cleavage reactions . However, these methods generally require toxic cyanide and heat.…”

“…General methods for the synthesis of nitriles include dehydration of amides, [4] formal acid-nitrile exchange, [5] Sandmeyer and Rosenmund-von Braun reactions, [6] transition-metal-catalysed cyanation, [7] electrophilic cyanide transfer, [8] and radical-type cleavage reactions. [9] However, these methods generally require toxic cyanide and heat. Cyanidefree routes to nitriles are possible starting from aldehydes (using azide,h ydroxylamine or ammonium salts as nitrogen source), [10] amines (in presence of metal catalysts or catalytic TEMPO or stoichiometric oxidants), [11] azides, [12] pre-formed oximes, [13] organic halides, [14] or arenes.…”

Aerobic Oxidative Functionalization of Indoles

“…[75] The copper-promoted CN triple bond cleavage of coordinated cyanide anion under oxygen atmosphere was disclosed by You and Lei. [76] Hence, the nitrogen atom was transferred to various aldehydes to form aryl, heteroaryl, and vinyl nitriles. This protocol provides a viable entry to indole-3-carbonitriles from indole-3carbaldehydes under facile CuBr 2 /O 2 conditions.…”

Sulfuryl Fluoride Mediated Conversion of Aldehydes to Nitriles

“…[32] A mild oxidative conversion of aldehydes to nitriles in the presence of an oxoammonium salt and hexamethyldisilazane (HMDS) was developed by Bailey and Leadbeater. [33] Recent oxidativem ethodsi nclude aerobic copper-promoted cleavage of cyanide triple bond reported by You, [34] and iodine catalyzed oxidative transformation of aldehydest on itrilesu sing ammonium acetate and tert-butyl hydroperoxide( TBHP) as the oxidant reported by Shen. [35] We describe here ap ractical directc onversion of aldehydes to nitriles whiche mploys stable and readily available reagents under mild conditions.…”