Electrochemical approach to direct homogeneous chemical cyanation of ferricenium salts: The complexing of system components

Tricyanated Ferrocenes; Isolation, structure, electrochemistry and DFT calculations

“…Compound 3 d was characterized by 1 H, 13 C NMR and IR spectra as well as by HRMS and also yielded crystals that were suitable for an X‐ray diffraction study. 2 c has been reported before (see also above) [15,20] …”

“…2 c has been reported before (see also above). [15,20] From our experience with cymantrene chemistry we knew, that pentabromocyclopentadienyl complexes are also good starting materials for the perfunctionalization of a cyclopentadienyl ring. [30] The reactivity of 1,2,3,4,5-pentabromoferrocene (5 a) has apparently not yet been studied.…”

“…[10] Cyanoferrocene 1 c, first reported in 1957, [11] is a generally wellstudied compound (156 references according to SciFinder n , accessed on January 10th, 2022), and many synthetic approaches have been reported, with many different starting materials, and yields between 5 and 90 %. [9,[11][12][13][14][15][16][17][18][19][20] . In contrast to this, there are rather few reports on the three isomeric dicyanoferrocenes (24 entries on 1,1'-, two entries on 1,2-and one on 1,3-dicyanoferrocene) and none on ferrocenes with three or more cyano substituents.…”

Efficient one-pot synthesis of cyanoferrocene from ferrocenecarboxaldehyde using NH2OH·HCl/KI/ZnO/CH3CN system

“…Zhang and co-workers prepared cyanoferrocene in 60% yield by refluxing ferrocenecarboxaldehyde with N-methylpyrrolidone, Et 3 N and NH 2 OH AE HCl [18]. Nekrasov and Yur'eva synthesized cyanoferrocene in 86% yield by cyanation of ferricenium salts with hydrocyanic acid through an electrochemical process [19]. Although, since its discovery, ferrocene and its derivatives are among the most thoroughly studied compounds, we were surprised that there has been limited study of ferrocenylnitriles.…”

“…Therefore, the development of a general synthetic entry to cyanoferrocene would be great interest. Although numerous methods are known for preparation of nitriles [9,10], SciFinder search has revealed only few reports for the synthesis of cyanoferrocene [17][18][19]. Pauson research group tried several procedures to synthesize cyanoferrocene but the highest yield (78%) was obtained by the dehydration of the corresponding oximes with dicyclohexylcarbodiimide [17].…”