Nitrene and Carbene Transfer Catalyzed by Metalloporphyrins

Mansuy, Daniel; Mahy, J.

doi:10.1007/978-94-017-2247-6_6

Cited by 17 publications

(12 citation statements)

References 96 publications

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“…Intramolecular N-alkylation of the planar N4 macrocycle by the axial carbon has also been found in iron−carbene porphyrin chemistry. , However, any three-membered ring formed is transient, with the M−N bond becoming disrupted. The porphyrin denticity is not increased.…”

Section: Resultsmentioning

confidence: 90%

Novel Chemistry of Carbon Bound to Cobalt in Organocobalt Complexes Related to B12

1996

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A rare Co−N−C three-membered ring has been formed by a novel pathway involving a facile interligand nucleophilic addition of an equatorial nitrogen donor to a ligated axial carbon in some organocobalt complexes. The highly distorted structure of a typical resulting complex provides clear experimental evidence useful in assessing hypotheses and computations concerning Co−C bond activation in B12 chemistry. Treatment of R = −CH2X (X = halogen) derivatives of imine/oxime B12 models of the type [LCo((DO)(DOH)pn)R]+ with base afforded major products with striking NMR spectral features in common, e.g., two one-proton olefinic doublets (J ≈ 3 Hz) and two one-proton singlets. The X-ray structure for the pyridine (py) derivative [pyCo(N-CH2-CHEL)]+ (1) reveals two unexpected features: a three-membered metallocycle containing an η2-aminomethylene group, and an enamine (N−CCH2) in place of one imine moiety (NC−CH3). The C−Co−N ring angle is acute (43.7°) with the distortion of the coordination sphere concentrated in the Co−C and the Co−N ring linkages, which move away from the normal pseudooctahedral positions. Studies of the formation of the aqua analog of 1, [H2OCo(N-CH2-CHEL)]+ (3), in aqueous solution suggest that the initial intermediate formed is deprotonated at one imine methyl. Ring closure in the short-lived deprotonated intermediate is facile. Published calculations predict that such ring closure could occur and that, of two processes which could facilitate Co−C bond cleavage (θ-bending of the N−Co−C angle and φ-bending of the Co−C−C angle), the latter factor should be more significant in weakening the Co−C bond. There is large θ-bending in 1; thus, the new metallocyclic B12 analogs afford the first experimental test of these calculations. Our findings that the Co−C bond in 1 is short and that the bond did not readily cleave support the predictions of the calculations.

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Section: Resultsmentioning

confidence: 90%

Novel Chemistry of Carbon Bound to Cobalt in Organocobalt Complexes Related to B12

1996

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“…In the case of R = Ph, R‘ = COOMe (complex 8 , Scheme ) we can suppose the labilized carbene carbon bridging the metal and the meso-carbon. A bridging bonding mode of the carbene carbon, like that observed between iron and one of the nitrogens of the porphyrin, is, however, prevented by the distance between the metal and the meso- carbon. Therefore, the attack at the meso-carbon by the carbene is followed by a rearrangement of the carbene fragment to a geometrically more appropriate bridging unit, such as the one in complex 11 .…”

Section: Resultsmentioning

confidence: 90%

Ruthenium−Carbene Functionality Bonded to Dibenzotetramethyltetraaza[14]annulene: Metal-to-Macrocycle Ligand-Induced Carbene Migration

Klose¹,

Solari²,

Hesschenbrouck³

et al. 1999

Organometallics

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This report contains the chemistry of the ruthenium−carbene functionality bonded to the dibenzotetramethyltetraaza[14]annulene dianion, tmtaa. [{Ru(tmtaa)}2(μ-C8H12)], 1, was the most appropriate starting material, as it contains a labile olefin, which can be displaced by a number of ligands to give [Ru(tmtaa)(L)(L‘)] [L = L‘ = Py, 2; L = CO, L‘ = thf, 3; L = ButNC, L‘ = thf, 4; L = L‘ = ButNC, 5]. Reaction of 1 with diazoalkanes led to the displacement of the olefin and gave the corresponding carbene derivatives [Ru(tmtaa)(CRR‘)] [R = R‘ = Ph, 6; R = Ph, R‘ = H, 7; R = Ph, R‘ = COOMe, 8], which have square-pyramidal structures. Complexes 7 and 8 underwent a remarkable labilization of the carbene functionality in the reaction with carbon monoxide, while 6 was only converted to the corresponding carbonyl [Ru(tmtaa)(CPh2)(CO)], 10, by CO. The reaction of 7 with both CO and ButNC led to the migration of the carbene to one of the metalladiimino rings of the ligands in 12 and 13, while the reaction of 8 with both CO and ButNC enabled us to intercept the preliminary product of a free-radical-type migration of the carbene to the tmtaa ligand, with the isolation of 11 and 14. The ligand (CO or ButNC)-induced migration of the CR2 fragment to the macrocycle seemed to proceed via a carbene mechanism in the case of 7, while 8 seemed to prefer a free-radical-like pathway. This assumption was further supported by extended Hückel calculations and by the reaction of 6−8 with ligands of different σ/π donor/acceptor capability. The pyridine converted 6−8 to the corresponding coordinate adducts, 15−17, while the reaction of 7 with PMe3 led to the formation of [Ru(tmtaa)(PMe3)2] and stilbenes, via a plausible carbene mechanism. The reaction of 8 with PMe3 proceeded through a free-radical pathway leading to 19, which has a structure similar to 11 and 14. The ligand-induced labilization of the metallacarbene functionality in the macrocyclic environment was analyzed using the extended Hückel calculations.

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“…Other metal complexes that catalyze metal nitrene CÀH insertion reactions, include metalloporphyrins [12,39], silver [21,40], copper [22], palladium [41] and gold [42] complexes. Other metal complexes that catalyze metal nitrene CÀH insertion reactions, include metalloporphyrins [12,39], silver [21,40], copper [22], palladium [41] and gold [42] complexes.…”

Section: H El Ene Lebelmentioning

confidence: 99%

“…Standard catalytic methods to produce CÀN bonds involve functional group manipulations, such as reductive amination of carbonyl compounds [2], addition of nucleophiles to imines [3], hydrogenation of enamides [4][5][6][7][8], hydroamination of olefins [9] or a CÀN coupling reaction [10,11]. Recently, the direct and selective introduction of a nitrogen atom into a CÀH bond via a metal nitrene intermediate has appeared as an attractive alternative approach for the formation of CÀN bonds [12][13][14][15][16][17][18][19][20][21][22][23][24].Copper-catalyzed decomposition of benzenesulfonyl azide in the presence of cyclohexene was the first reported evidence of a metal-catalyzed nitrene insertion reaction [25]. This seminal discovery was then followed by the pioneering work of Breslow and Gellman who introduced the use of iminoiodinanes as metal nitrene precursors as well as rhodium dimer complexes as catalysts [26,27].…”

mentioning

confidence: 99%

Rhodium‐Catalyzed CH Aminations

Lebel

2010

Catalyzed Carbon‐Heteroatom Bond Formation

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The formation of CÀN bonds is an important transformation in organic synthesis, as the amine functionality is found in numerous natural products and plays a key role in many biologically active compounds [1]. Standard catalytic methods to produce CÀN bonds involve functional group manipulations, such as reductive amination of carbonyl compounds [2], addition of nucleophiles to imines [3], hydrogenation of enamides [4][5][6][7][8], hydroamination of olefins [9] or a CÀN coupling reaction [10,11]. Recently, the direct and selective introduction of a nitrogen atom into a CÀH bond via a metal nitrene intermediate has appeared as an attractive alternative approach for the formation of CÀN bonds [12][13][14][15][16][17][18][19][20][21][22][23][24].Copper-catalyzed decomposition of benzenesulfonyl azide in the presence of cyclohexene was the first reported evidence of a metal-catalyzed nitrene insertion reaction [25]. This seminal discovery was then followed by the pioneering work of Breslow and Gellman who introduced the use of iminoiodinanes as metal nitrene precursors as well as rhodium dimer complexes as catalysts [26,27]. They showed the formation of the corresponding benzosultam in 86% yield in the presence of rhodium (II) acetate dimer (Rh 2 (OAc) 4 ) via an intramolecular metal nitrene CÀH bond insertion reaction (Eq. (5.1)). 86% Rh 2 (OAc) 4 (5 mol%) MeCN, rt S N I Ph O O S NH O O ð5:1ÞM€ uller then intensively studied rhodium dimer complexes as catalysts for the intermolecular amination of alkanes using iminoiodinanes, typically PhI¼NTs and PhI¼NNs [28][29][30]. Good yields were obtained for amination of benzylic, allylic and tertiary CÀH bonds, which are the most reactive CÀH bonds towards metal nitrenes. For instance the amination of indane provided the corresponding benzylic amine in Catalyzed Carbon-Heteroatom Bond Formation. Edited

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Nitrene and Carbene Transfer Catalyzed by Metalloporphyrins

Cited by 17 publications

References 96 publications

Novel Chemistry of Carbon Bound to Cobalt in Organocobalt Complexes Related to B12

Novel Chemistry of Carbon Bound to Cobalt in Organocobalt Complexes Related to B12

Ruthenium−Carbene Functionality Bonded to Dibenzotetramethyltetraaza[14]annulene: Metal-to-Macrocycle Ligand-Induced Carbene Migration

Rhodium‐Catalyzed CH Aminations

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