- Formation of quaternary carbons through cobalt-catalyzed C(sp3)-C(sp3) Negishi cross-coupling
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Formation of all-carbon-substituted quaternary carbons is a key challenge in organic and medicinal chemistry. We report a cobalt-catalyzed C(sp3)-C(sp3) cross-coupling that allows for the introduction of benzyl, heteroarylmethylzinc and allyl groups to halo-carbonyl substrates. The cross-coupling reaction is selective for C(sp3)-over C(sp2)-halides, in contrast to most used catalytic metals, and allows access to novel scaffolds of pharmaceutical interest. NMR mechanistic studies suggest the presence of Co(0) complexes as catalytic species. This journal is
- Palao, Eduardo,López, Enol,Torres-Moya, Iván,De La Hoz, Antonio,Díaz-Ortiz, ángel,Alcázar, Jesús
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p. 8210 - 8213
(2020/08/17)
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- METHOD FOR ALCOHOLYSIS OF AMIDE
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Provided is a method for the alcoholysis of an amide. The method comprises subjecting an amide-containing compound to alcoholysis under alkaline conditions using an epoxy compound as an accelerant of alcoholysis.
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Paragraph 0041-0042; 0044-0066; 0075-0077; 0090-0091; 0129-0
(2020/03/01)
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- An Epoxide-Mediated Deprotection Method for Acidic Amide Auxiliary
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A practical method for the removal of a versatile acidic amide auxiliary has been developed. Facile alcoholysis of the amide in the presence of KOAc is enabled by an epoxide, which mechanistically resembles the removal of the Myers' auxiliary. The protocol has been applied to the removal of a variety of amide substrates and their C-H functionalization products with high efficiency and low cost, representing a step forward toward the development of a versatile directing group for C-H activation.
- Pei, Qing-Lan,Che, Guan-Da,Zhu, Ru-Yi,He, Jian,Yu, Jin-Quan
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supporting information
p. 5860 - 5863
(2017/11/10)
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- Method for amide alcoholysis
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The invention provides a method for amide alcoholysis. The method comprises the following steps: using an epoxy compound as an accelerator, and performing alcoholysis on an amide-containing compound under an alkaline condition. The above method is convenient and easy to operate, pure products can be obtained through post-treatment which just needs conventional separation steps, and the epoxy compound is low in costs, thus production and operation costs and three wastes (waste water, waste gas and solid waste) treatment risks and costs can be greatly reduced; when the above method is used, reaction conditions are mild, the method can be compatible with various substituent groups and functional groups, obtains good yields aiming at various amides with different structures, and is wide in substrate application range; an environmentally friendly, economic and practical high-efficiency method for conversion of amides into more useful esters is provided; and the above alcoholysis reaction cannot be influenced by impurities of a previous-step C-H activating reaction system, an intermediate purification step is saved, and two-step reactions of a C-H activating reaction and an amide alcoholysis reaction can be linked.
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Paragraph 0049; 0040; 0051; 0122; 0123; 0124; 0146-0149
(2017/12/28)
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- One-pot reduction of aryl iodides using 4-DMAP methiodide salt
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An efficient one-pot procedure is described for the reduction of aryl iodides to aryl anions using a structurally simple bis-pyridinylidene electron donor, prepared in situ by treating 4-DMAP methiodide salt with base. The results show (i) that pyridinylidene carbenes can be easily used for intermolecular C-C bond formation, (ii) that bis-pyridinylidenes demonstrate superior robustness compared to electron-donor systems based on bis-imidazolylidenes, and (iii) that electron-donor strength is enhanced in the simplified DMAP-based donor. Deuterated analogues of this donor also provide mechanistic information on the source of protons when the aryl anions are quenched in situ. Georg Thieme Verlag Stuttgart.
- Garnier, Jean,Murphy, John A.,Zhou, Sheng-Ze,Turner, Andrew T.
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experimental part
p. 2127 - 2131
(2009/05/07)
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- The generation of aryl anions by double electron transfer to aryl iodides from a neutral ground-state organic super-electron donor
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(Chemical Equation Presented) It takes two to cyclize: Aryl halides are reduced to aryl anions by double electron transfer from the neutral ground-state electron donor 1 (see scheme), as shown by the formation of a cyclic ketone (2). The reduced compound (3) is also formed. Calculations show that the loss of two electrons from 1 is both thermodynamically and kinetically viable and generates a more planar resonance-stabilized structure.
- Murphy, John A.,Zhou, Sheng-Ze,Thomson, Douglas W.,Schoenebeck, Franziska,Mahesh, Mohan,Park, Stuart R.,Tuttle, Tell,Berlouis, Leonard E. A.
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p. 5178 - 5183
(2008/03/27)
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- 5,5-Dimethyl-1,4,2-dioxazoles as versatile aprotic hydroxamic acid protecting groups
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5,5-Dimethyl-1,4,2-dioxazoles are readily installed by transketalization of 2,2-diethoxypropane, where both the NH and OH moieties are protected in a nonprotic form. The dioxazoles are stable to a wide variety of reaction conditions and readily revert back to the hydroxamic acid by treatment with Nafion-H in 2-propanol. The method is applicable to primary, secondary, tertiary, and aromatic hydroxamic acids, and the acidity of the protons adjacent to the dioxazole allows α-functionalization.
- Couturier, Michel,Tucker, John L.,Proulx, Caroline,Boucher, Ghislain,Dube, Pascal,Andresen, Brian M.,Ghosh, Arun
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p. 4833 - 4838
(2007/10/03)
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- Practical hydroxymethylation of aldehydes and ketones via pinacol cross-coupling reactions with paraformaldehyde
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A general and practical method for the direct hydroxymethylation of aldehydes and ketones via pinacol cross-coupling with paraformaldehyde is described. The reaction is promoted by vanadium(II) ions which are conveniently generated from the reduction of VCl3(THF)3 with zinc dust. Excellent yields of terminal diols are obtained and stereoselective coupling is observed with some chiral aldehydes and ketones.
- Park, Jeonghan,Pedersen, Steven F.
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p. 2069 - 2080
(2007/10/02)
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- Cephalosporin derivatives
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Cephemcarboxylic acid esters of the general formula STR1 pharmaceutical preparations which are active against bacterial infections, which contain such cephem derivatives, a process for the preparation of the cephem derivatives and the pharmaceutical preparations, and also the use of the cephem derivatives for combating bacterial infections.
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