15260-65-8Relevant articles and documents
Synthesis and Reduction of 2,2-diaryl-1-nitroethylenes by using a chiral and a non chiral NADH model in the pyrrolopyridine series
Levacher, Vincent,Valque, Claude,Coupa, Sophie,Dupas, Georges,Queguiner, Guy,Bourguignon, Jean
, p. 1211 - 1215 (1996)
Reduction of 2,2-diphenyl-1-nitroethylene (1) and 2-(2-pyridyl)-2-phenyl-1-nitroethylene (5) is achieved by using the NADH model in the pyrrolopyridine series 2a to give 2,2-diphenyl-1-nitroethane (3) and 2-(2-pyridyl)-2-phenyl-1-nitroethane (7) respectively in 40% yield. The asymmetric reduction of 2-(2-pyridyl)-2-phenyl-1-nitroethylene by the chiral NADH model 2b is studied. Thus, 2-(2-pyridyl)-2-phenyl-1-nitroethane (7) is obtained in 15 to 32% yield. The stereocontrol of the reduction proved to be dependent on the amount of magnesium ions.
Reactivity Diversification - Synthesis and Exchange Reactions of Cobalt and Iron 2-Alkenylpyridine/-pyrazine Complexes Obtained by Vinylic C(sp2)-H Activation
Beck, Robert,Camadanli, Sebnem,Fl?rke, Ulrich,Klein, Hans-Friedrich
, p. 2543 - 2559 (2015)
Abstract The reactivity of 2-alkenylpyridine derivatives with trimethylphosphane-supported iron- and cobalt-methyl adducts were investigated and provided a series of C,N-cyclometalated complexes through smooth vinyl C(sp2)-H activation. The rea
Photoenzymatic Hydrogenation of Heteroaromatic Olefins Using ‘Ene’-Reductases with Photoredox Catalysts
Biegasiewicz, Kyle F.,Black, Michael J.,Chung, Megan M.,Hyster, Todd K.,Meichan, Andrew J.,Nakano, Yuji,Sandoval, Braddock A.,Zhu, Tianyu
, p. 10484 - 10488 (2020/04/29)
Flavin-dependent ‘ene’-reductases (EREDs) are highly selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to the corresponding neutral benzylic radical in solution. DFT calculations reveal this radical to be “dynamically stable”, suggesting it is sufficiently long-lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer. This reduction mechanism is distinct from the native one, highlighting the opportunity to expand the synthetic capabilities of existing enzyme platforms by exploiting new mechanistic models.
Catalytic Enantioselective Synthesis of α-Chiral Azaheteroaryl Ethylamines by Asymmetric Protonation
Xu, Chao,Muir, Calum W.,Leach, Andrew G.,Kennedy, Alan R.,Watson, Allan J. B.
supporting information, p. 11374 - 11377 (2018/08/28)
The direct enantioselective synthesis of chiral azaheteroaryl ethylamines from vinyl-substituted N-heterocycles and anilines is reported. A chiral phosphoric acid (CPA) catalyst promotes dearomatizing aza-Michael addition to give a prochiral exocyclic aryl enamine, which undergoes asymmetric protonation upon rearomatization. The reaction accommodates a broad range of N-heterocycles, nucleophiles, and substituents on the prochiral centre, generating the products in high enantioselectivity. DFT studies support a facile nucleophilic addition based on catalyst-induced LUMO lowering, with site-selective, rate-limiting, intramolecular asymmetric proton transfer from the ion-paired prochiral intermediate.
β-Selective Reductive Coupling of Alkenylpyridines with Aldehydes and Imines via Synergistic Lewis Acid/Photoredox Catalysis
Lee, Katarzyna N.,Lei, Zhen,Ngai, Ming-Yu
, p. 5003 - 5006 (2017/05/04)
Umpolung (polarity reversal) strategies of aldehydes and imines have dramatically expanded the scope of carbonyl and iminyl chemistry by facilitating reactions with non-nucleophilic reagents. Herein, we report the first visible light photoredox-catalyzed β-selective reductive coupling of alkenylpyridines with carbonyl or iminyl derivatives with the aid of a Lewis acid co-catalyst. Our process tolerates complex molecular scaffolds (e.g., sugar, natural product, and peptide derivatives) and is applicable to the preparation of compounds containing a broad range of heterocyclic moieties. Mechanistic investigations indicate that the key step involves single-electron-transfer reduction of aldehydes or imines followed by the addition of resulting ketyl or α-aminoalkyl radicals to Lewis acid-activated alkenylpyridines.
