- Photoactive electron donor-acceptor complex platform for Ni-mediated C(sp3)-C(sp2) bond formation
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A dual photochemical/nickel-mediated decarboxylative strategy for the assembly of C(sp3)-C(sp2) linkages is disclosed. Under light irradiation at 390 nm, commercially available and inexpensive Hantzsch ester (HE) functions as a potent organic photoreductant to deliver catalytically active Ni(0) species through single-electron transfer (SET) manifolds. As part of its dual role, the Hantzsch ester effects a decarboxylative-based radical generation through electron donor-acceptor (EDA) complex activation. This homogeneous, net-reductive platform bypasses the need for exogenous photocatalysts, stoichiometric metal reductants, and additives. Under this cross-electrophile paradigm, the coupling of diverse C(sp3)-centered radical architectures (including primary, secondary, stabilized benzylic, α-oxy, and α-amino systems) with (hetero)aryl bromides has been accomplished. The protocol proceeds under mild reaction conditions in the presence of sensitive functional groups and pharmaceutically relevant cores.
- Kammer, Lisa Marie,Badir, Shorouk O.,Hu, Ren-Ming,Molander, Gary A.
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p. 5450 - 5457
(2021/05/05)
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- Photoinduced Nickel-Catalyzed Deaminative Cross-Electrophile Coupling for C(sp2)-C(sp3) and C(sp3)-C(sp3) Bond Formation
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The construction of C-C bonds through cross-coupling between two electrophiles in the absence of excess metallic reducing agents is a desirable objective in chemistry. Here, we show that N-alkylpyridinium salts can be efficiently merged with aryl or alkyl halides in an intermolecular fashion, affording products in up to 92% yield at ambient temperature. These reactions harness the ability of N-alkylpyridinium salts to form electron donor-acceptor complexes with Hantzsch esters, enabling photoinduced single-electron transfer and fragmentation to afford alkyl radicals that are subsequently trapped by a Ni-based catalytic species to promote C(sp2)-C(sp3) and C(sp3)-C(sp3) bond formation. The operationally simple protocol is applicable to site-selective cross-coupling and tolerates diverse functional groups, including those that are sensitive toward metal reductants.
- Koh, Ming Joo,Wei, Yi,Yang, Tao
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p. 6519 - 6525
(2021/06/25)
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- Deaminative Reductive Arylation Enabled by Nickel/Photoredox Dual Catalysis
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Described is a cross-electrophilic, deaminative coupling strategy harnessing Katritzky salts as a new species of electrophile in Ni/photoredox dual catalytic reductive cross-coupling reactions. Distinguishing features of this arylation protocol include its mild reaction conditions, high chemoselectivity, and adaptability to a variety of complex substrates [i.e., pyridinium salts derived from amines and partners derived from (hetero)aryl bromides].
- Yi, Jun,Badir, Shorouk O.,Kammer, Lisa Marie,Ribagorda, Mariá,Molander, Gary A.
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supporting information
(2019/05/07)
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- Nickel-catalyzed C-N bond activation: Activated primary amines as alkylating reagents in reductive cross-coupling
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Nickel-catalyzed reductive cross coupling of activated primary amines with aryl halides under mild reaction conditions has been achieved for the first time. Due to the avoidance of stoichiometric organometallic reagents and external bases, the scope regarding both coupling partners is broad. Thus, a wide range of substrates, natural products and drugs with diverse functional groups are tolerated. Moreover, experimental mechanistic investigations and density functional theory (DFT) calculations in combination with wavefunction analysis have been performed to understand the catalytic cycle in more detail.
- Yue, Huifeng,Zhu, Chen,Shen, Li,Geng, Qiuyang,Hock, Katharina J.,Yuan, Tingting,Cavallo, Luigi,Rueping, Magnus
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p. 4430 - 4435
(2019/04/29)
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- Ru/Ni Dual Catalytic Desulfinative Photoredox Csp2-C sp3Cross-Coupling of Alkyl Sulfinate Salts and Aryl Halides
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A mild Ru/Ni dual catalytic desulfinative photoredox Csp2-Csp3 cross-coupling reaction of alkyl sulfinate salts with aryl halides has been developed. The optimized catalyst system, consisting of Ru(bpy)3Cl2, Ni(COD)2, and DBU, smoothly mediates the coupling of a diverse set of secondary and primary nonactivated alkyl sulfinate salts with a broad range of electron-deficient aryl bromides, electron-rich aryl iodides, and heteroaryl bromides under irradiation with blue light. The procedure is ideal for late-stage introduction of alkyl groups on pharmaceutical intermediates, and the Csp2-Csp3 cross-coupling reaction allowed the rapid synthesis of caseine kinase 1 inhibitor analogues via a parallel medicinal chemistry effort.
- Knauber, Thomas,Chandrasekaran, Ramalakshmi,Tucker, Joseph W.,Chen, Jinshan Michael,Reese, Matthew,Rankic, Danica A.,Sach, Neal,Helal, Christopher
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supporting information
p. 6566 - 6569
(2017/12/26)
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- Alcohols as Latent Coupling Fragments for Metallaphotoredox Catalysis: Sp3-sp2 Cross-Coupling of Oxalates with Aryl Halides
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Alkyl oxalates, prepared from their corresponding alcohols, are engaged for the first time as carbon radical fragments in metallaphotoredox catalysis. In this report, we demonstrate that alcohols, native organic functional groups, can be readily activated with simple oxalyl chloride to become radical precursors in a net redox-neutral Csp3-Csp2 cross-coupling with a broad range of aryl halides. This alcohol-activation coupling is successfully applied to the functionalization of a naturally occurring steroid and the expedient synthesis of a medicinally relevant drug lead.
- Zhang, Xiaheng,MacMillan, David W.C.
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p. 13862 - 13865
(2016/11/06)
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- ANTI-INFECTIVE COMPOUNDS
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The present invention relates to small molecule compounds and their use in the treatment of bacterial infections, in particular Tuberculosis.
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Page/Page column 35
(2015/02/25)
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- HETEROCYCLIC MODULATORS OF LIPID SYNTHESIS AND COMBINATIONS THEREOF
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Heterocyclic modulators of lipid synthesis are provided as well as pharmaceutically acceptable salts thereof; pharmaceutical compositions comprising such compounds; and methods of treating conditions characterized by disregulation of a fatty acid synthase pathway by the administration of such compounds and combinations of such compounds and other therapeutic agents.
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Page/Page column 74
(2015/07/07)
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- HETEROCYCLIC MODULATORS OF LIPID SYNTHESIS
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Heterocyclic modulators of lipid synthesis are provided as well as pharmaceutically acceptable salts thereof; pharmaceutical compositions comprising such compounds; and methods of treating conditions characterized by disregulation of a fatty acid synthase pathway by the administration of such compounds.
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Page/Page column 59; 60
(2014/01/18)
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- Mild negishi cross-coupling reactions catalyzed by acenaphthoimidazolylidene palladium complexes at low catalyst loadings
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Considering that the strong σ-donor property of ylidenes derived from π-extended imidazolium salts is conducive to increasing the catalytic activity of the resulting palladium N-heterocyclic carbene complexes, robust acenaphthoimidazol-ylidene palladium complexes 3a-c with varying bulky substituted groups were prepared from the corresponding acenaphthoimidazolium chlorides by heating with PdCl2 and K2CO3 in neat 3-chloropyridine in satisfactory yields. Even at a catalyst loading as low as 0.25 mol %, complex 3a exhibited extremely high catalytic activity toward Negishi cross-coupling of alkylzinc reagents with a wide range of (hetero)aryl halides under mild reaction conditions within 30 min. Besides a great number of bromoarenes, various less expensive and inactive (hetero)aryl chlorides were coupled successfully with the alkyl- and arylzinc reagents, in which active functional groups (such as -NH2) were well tolerated even in one-pot dicoupling transformations without protection. In addition, in the case of coupling with secondary alkylzinc reagents, undesired β-hydride elimination leading to isomerized linear products was efficaciously suppressed. The catalyst system also displayed superiority in the construction of heterobiaryls through the coupling of heteroarylzinc reagents and heterocylic chloroarenes which were hardly accessible from the corresponding organoboron reagents by Suzuki-coupling reactions. Therefore, the protocol described in this paper represents a mild, general, and scalable approach to access various structurally intriguing and functionalized (hetero)aryls.
- Liu, Zelong,Dong, Ningning,Xu, Mizhi,Sun, Zheming,Tu, Tao
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p. 7436 - 7444
(2013/09/02)
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- Palladium-catalyzed asymmetric coupling cyclization of terminal γ-allenols with aryl iodides
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A Pd-catalyzed asymmetric coupling cyclization of γ-allenols has been developed. Styrenyl derivatives can be prepared in 60-86% yields with ee values ranging from 85-92%.
- Xie, Xi,Ma, Shengming
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supporting information
p. 5693 - 5695
(2013/07/05)
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- Imidazopyridine-based fatty acid synthase inhibitors that show anti-HCV activity and in vivo target modulation
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Potent imidazopyridine-based inhibitors of fatty acid synthase (FASN) are described. The compounds are shown to have antiviral (HCV replicon) activities that track with their biochemical activities. The most potent analogue (compound 19) also inhibits rat FASN and inhibits de novo palmitate synthesis in vitro (cell-based) as well as in vivo.
- Oslob, Johan D.,Johnson, Russell J.,Cai, Haiying,Feng, Shirley Q.,Hu, Lily,Kosaka, Yuko,Lai, Julie,Sivaraja, Mohanram,Tep, Samnang,Yang, Hanbiao,Zaharia, Cristiana A.,Evanchik, Marc J.,McDowell, Robert S.
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p. 113 - 117
(2013/02/26)
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