864832-30-4Relevant academic research and scientific papers
Olefin Hydroarylation Catalyzed by a Single-Component Cobalt(-I) Complex
Suslick, Benjamin A.,Tilley, T. Don
supporting information, p. 1495 - 1499 (2021/03/03)
A single-component Co(-I) catalyst, [(PPh3)3Co(N2)]Li(THF)3, has been developed for olefin hydroarylations with (N-aryl)aryl imine substrates. More than 40 examples were examined under mild reaction conditions to afford the desired alkyl-arene product in good to excellent yields. Catalysis occurs in a regioselective manner to afford exclusively branched products with styrene-derived substrates or linear products for aliphatic olefins. Electron-withdrawing functional groups (e.g., -F, -CF3, and -CO2Me) were tolerated under the reaction conditions.
Mechanistic Interrogation of Alkyne Hydroarylations Catalyzed by Highly Reduced, Single-Component Cobalt Complexes
Suslick, Benjamin A.,Tilley, T. Don
supporting information, p. 11203 - 11218 (2020/07/08)
Highly reactive catalysts for ortho-hydroarylations of alkynes have previously been reported to result from activation of CoBr2 by Grignard reagents, but the operative mechanism and identity of the active cobalt species have been undefined. A mechanistic analysis of a related system, involving hydroarylations of a (N-aryl)aryl ethanimine with diphenylacetylene, was performed using isolable reduced Co complexes. Studies of the stoichiometric reaction of Co(I) or Co(II) precursors with CyMgCl implicated catalyst initiation via a β-H elimination/deprotonation pathway. The resulting single-component Co(-I) complex is proposed as the direct pre-catalyst. Michaelis-Menten enzyme kinetic studies provide mechanistic details regarding the catalytic dependence on substrate. The (N-aryl)aryl ethanimine substrate exhibited saturation-like behavior, whereas alkyne demonstrated a complex dependency; rate inhibition and promotion depend on the relative concentration of alkyne to imine. Activation of the aryl C-H bond occurred only in the presence of coordinated alkyne, which suggests operation of a concerted metalation-deprotonation (CMD) mechanism. Small primary isotope effects are consistent with a rate-determining C-H cleavage. Off-cycle olefin isomerization catalyzed by the same Co(-I) active species appears to be responsible for the observed Z-selectivity.
Efficient Synthesis of Amines by Iron-Catalyzed C=N Transfer Hydrogenation and C=O Reductive Amination
Facchini, Sofia Vailati,Cettolin, Mattia,Bai, Xishan,Casamassima, Giuseppe,Pignataro, Luca,Gennari, Cesare,Piarulli, Umberto
supporting information, p. 1054 - 1059 (2018/01/27)
Here we report the catalytic transfer hydrogenation (CTH) of non-activated imines promoted by a Fe-catalyst in the absence of Lewis acid co-catalysts. Use of the (cyclopentadienone)iron complex 1, which is much more active than the classical ‘Kn?lker complex’ 2, allowed to reduce a number of N-aryl and N-alkyl imines in very good yields using iPrOH as hydrogen source. The reaction proceeds with relatively low catalyst loading (0.5–2 mol%) and, remarkably, its scope includes also ketimines, whose reduction with a Fe-complex as the only catalyst has little precedents. Based on this methodology, we developed a one-pot CTH protocol for the reductive amination of aldehydes/ketones, which provides access to secondary amines in high yield without the need to isolate imine intermediates. (Figure presented.).
Manganese-Catalyzed C?H Annulation of Ketimines with Allenes: Stereoselective Synthesis of 1-Aminoindanes
Lei, Chong,Peng, Lijie,Ding, Ke
supporting information, p. 2952 - 2958 (2018/08/17)
A manganese-catalyzed C?H annulation of ketimines with poly-substituted ester-activated allenes toward the synthesis of 1-aminoindanes bearing two vicinal all-substituted carbon stereocenters and an exocyclic double bond was developed. The reaction featur
Solid Supported Chiral N-Picolylimidazolidinones: Recyclable Catalysts for the Enantioselective, Metal- and Hydrogen-Free Reduction of Imines in Batch and in Flow Mode
Porta, Riccardo,Benaglia, Maurizio,Annunziata, Rita,Puglisi, Alessandra,Celentano, Giuseppe
supporting information, p. 2375 - 2382 (2017/07/22)
A new class of solid supported chiral imidazolidinone organocatalysts for the catalytic reduction of imines with trichlorosilane has been developed. Polystyrene proved to be a more effective support than silica in terms of both chemical and stereochemical
C-H activation/functionalization catalyzed by simple, well-defined low-valent cobalt complexes
Fallon, Brendan J.,Derat, Etienne,Amatore, Muriel,Aubert, Corinne,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Petit, Marc
supporting information, p. 2448 - 2451 (2015/03/04)
A facile C-H activation and functionalization of aromatic imines is presented using low-valent cobalt catalysts. Using Co(PMe3)4 as catalyst we have developed an efficient and simple protocol for the C-H/hydroarylation of alkynes wit
Palladium-catalyzed condensation of N -aryl imines and alkynylbenziodoxolones to form multisubstituted furans
Lu, Beili,Wu, Junliang,Yoshikai, Naohiko
supporting information, p. 11598 - 11601 (2014/10/16)
A palladium(II) catalyst promotes condensation of an N-aryl imine and an alkynylbenziodoxolone derivative to afford a multisubstituted furan, whose substituents are derived from the alkynyl moiety (2-position), the imine (3- and 4-positions), and the 2-iodobenzoate moiety (5-position), along with an N-arylformamide under mild conditions. The 2-iodophenyl group of the furan product serves as a versatile handle for further transformations. A series of isotope-labeling experiments shed light on the bond reorganization process in this unusual condensation reaction, which includes cleavage of the C-C triple bond and fragmentation of the carboxylate moiety.
Asymmetric hydrogenation of N-alkyl and N-aryl ketimines using chiral cationic Ru(diamine) complexes as catalysts: The counteranion and solvent effects, and substrate scope
Chen, Fei,Ding, Ziyuan,He, Yanmei,Qin, Jie,Wang, Tianli,Fan, Qing-Hua
supporting information; experimental part, p. 5248 - 5257 (2012/08/08)
Asymmetric hydrogenation of N-alkyl and N-aryl ketimines catalyzed by chiral cationic η6-arene-(N-monosulfonylated diamine) Ru(II) complexes has been investigated. Strong counteranion and solvent effects on the enantioselectivity were observed. The ruthenium catalyst bearing non-coordinating BArF- anion was found to be particularly effective for the hydrogenation of acyclic and exocyclic N-alkyl ketimines in the presence of (Boc)2O in dichloromethane or even under solvent-free conditions, providing chiral amines with up to >99% ee and full conversions. Alternatively, the ruthenium catalyst bearing achiral phosphate anion together with corresponding phosphoric acid as the additive was also efficient for the hydrogenation of N-alkyl ketimines in the absence of (Boc)2O with excellent enantioselectivities and full conversions. For N-aryl ketimines lower enantiomeric excesses were observed by using the ruthenium catalyst bearing BArF- anion. This catalytic protocol thus provides a facile and practical access to optically active amines and has been successfully employed in the gram-scale synthesis of enantiomerically pure (+)-sertraline.
Asymmetric reduction of ketimines with trichlorosilane employing an imidazole derived organocatalyst
Gautier, Franois-Moana,Jones, Simon,Martin, Stephen J.
supporting information; experimental part, p. 229 - 231 (2009/03/11)
Organocatalysts for the asymmetric reduction of ketimines are presented that function well at low catalyst loadings providing chiral amines in good yield and enantioselectivity, the latter appearing to be independent of the ketimine substrate geometry.
Enantioselective hydrogenation of acyclic aromatic N-aryl imines catalyzed by an iridium complex of (S,S)-1,2-bis(tert-butylmethylphosphino)ethane
Imamoto, Tsuneo,Iwadate, Noriyuki,Yoshida, Kazuhiro
, p. 2289 - 2292 (2007/10/03)
An iridium(I) complex of (S,S)-1,2-bis(tert-butylmethylphosphino)ethane with tetrakis(3,5-bis(trifluoromethyl)phenyl)borate as the counterion catalyzes the hydrogenation of acyclic aromatic N-aryl imines under 1 atm of hydrogen pressure at room temperatur
