Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH3CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)

Elliot, David J.; Haukilahti, Sanna; Holah, D. G.; Hughes, Alan N.; Maciaszek, S.; Barton, Richard J.; Luo, Yanru; Robertson, B. E.

doi:10.1139/v88-285

Cited by 9 publications

(1 citation statement)

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“…The oxygen-atom-coordinated complexes are more stable than the nitrogen-atom-coordinated complexes 17a relatively few group 8−10 metal complexes with amide ligands have been isolated. − …”

Section: Introductionmentioning

confidence: 99%

Novel Ruthenium-Complex-Catalyzed Synthesis of Ureas from Formamides and Amines

et al. 1997

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Various N,N′-disubstituted and trisubstituted ureas were obtained in high yields by the ruthenium-complex-catalyzed dehydrogenation of N-substituted formamides and amines under reflux in mesitylene for 12 h under an argon atmosphere. From formanilide (1a) and aniline (2a), N,N ′-diphenylurea (3a) was obtained in 92% yield. During this reaction, a stoichiometric amount of gaseous hydrogen was spontaneously evolved; thus, the addition of a hydrogen acceptor was not required. Formamide itself, i.e., HCONH 2 (4), can also be used as a versatile carbonyl source. From HCONH 2 (4) and primary amines, the corresponding N,N′-disubstituted ureas were obtained in high yields together with the evolution of hydrogen and ammonia. To identify a catalytically active species, the stoichiometric reaction of RuCl 2 (PPh 3 ) 3 with formanilide (1a) was carried out in CH 2 Cl 2 at room temperature to give a novel oxygen-atom-bridged dinuclear ruthenium complex, Ru 2 (µ-Cl) 2 Cl 2 (µ-PhNH-CHO-O,O)(PPh 3 ) 4 (5), in 87% yield. Complex 5 showed a high catalytic activity for the synthesis of N,N ′-diphenylurea from formanilide (1a) and aniline (2a), and the stoichiometric reaction of 5 with aniline gave N,N ′-diphenylurea, which strongly suggests that complex 5 is the key intermediate in the RuCl 2 (PPh 3 ) 3 -catalyzed synthesis of ureas using formamides as a versatile carbonyl source.

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