2342-50-9Relevant academic research and scientific papers
Metal-free Photocatalytic Intermolecular anti-Markovnikov Hydroamination of Unactivated Alkenes
Li, Juncheng,Wang, Ting,Zhao, Gaoyuan
supporting information, p. 2650 - 2654 (2021/06/25)
The development of photocatalytic intermolecular hydroamination reaction between N-aminated dihydropyridines and unactivated alkenes is reported. Metal-free co-catalysts, rhodamine 6G and thiophenol, in presence of visible light are used to initiate the process. The transformation shows a broad substrate scope, both alkenes and amidyl radical can act as coupling partners. The radical strategy provides excellent anti-Markovnikov selectivity and regioselectivity in diene substrates.
Oxidative Amidation of Amines in Tandem with Transamidation: A Route to Amides Using Visible-Light Energy
Nandi, Jyoti,Vaughan, Matthew Z.,Sandoval, Arturo León,Paolillo, Joshua M.,Leadbeater, Nicholas E.
, p. 9219 - 9229 (2020/08/14)
A methodology is reported for preparing amides using amines as an acyl source. The protocol involves the visible-light-promoted oxidative amidation of amines with pyrazole to synthesize N-acyl pyrazoles followed by transamidation. By combining photoredox catalysis with oxoammonium cations in the presence of sodium persulfate as a terminal oxidant, the N-acyl pyrazoles could be prepared efficiently and effectively using blue LEDs. The transamidation step was performed without the need to purify the N-acyl pyrazole intermediate, and a range of amides were generated in good to excellent yields.
Metal-Free C-N or C-C Bond Cleavages of α-Azido Ketones: An Oxidative-Amidation Strategy for the Synthesis of α-Ketothioamides and Amides
Yu, Pei,Wang, Yuwei,Zeng, Zhigang,Chen, Yunfeng
, p. 14883 - 14891 (2019/11/11)
A novel metal-free oxidative-amidation strategy for the synthesis of α-ketothioamides and amides from α-azido ketones was developed. The C-H bond thionation of α-azido ketones with elemental sulfur could form α-ketothioacyl azide, which was then nucleophilically attacked by amines, causing the cleavage of the C-N bond to afford α-ketothioamides, while amides could be formed with the release of nitrogen gas and cyano anion in the presence of PhI(OAc)2 by selective C-C bond cleavage.
Integration of co2 reduction with subsequent carbonylation: Towards extending chemical utilization of co2
Lang, Xian-Dong,He, Liang-Nian
, p. , 2062 (2018/10/20)
Currently, it still remains a challenge to amplify the spectrum of chemical fixation of CO2, although enormous progress has been achieved in this field. In view of the widespread applications of CO in a myriad of industrial carbonylation processes, an alternative strategy is proposed in which CO2 reduction to CO is combined with carbonylation with CO generated ex situ, which affords efficiently pharmaceutically and agrochemically attractive molecules. As such, CO2 in this study was efficiently reduced by triphenysilane using CsF to CO in a sealed two-chamber reactor. Subsequently, palladium-catalyzed aminocar-bonylation, carbonylative Sonogashira coupling of aryl iodides, and rhodium(I)-mediated Pauson–Khand-type reaction proceeded smoothly to yield amides, alkynones, and bicyclic cy-clopentenones, respectively. Furthermore, the formed alkynones can further be successfully converted to a series of heterocycles, for example, pyrazoles, 3a-hydroxyisoxazolo[3,2-a]isoindol-8-(3aH)-one derivatives and pyrimidines in moderate yields. The striking features of this protocol include operational simplicity, high efficiency, and relatively broad application scope, which represents an alternative avenue for CO2 transformation.
Copper-catalyzed oxidative C(sp3)-H/N-H coupling of sulfoximines and amides with simple alkanes via a radical process
Teng, Fan,Sun, Song,Jiang, Yan,Yu, Jin-Tao,Cheng, Jiang
supporting information, p. 5902 - 5905 (2015/03/30)
A copper-catalyzed oxidative C(sp3)-H/N-H coupling of sulfoximines with simple alkanes was developed. This protocol involved C(sp3)-N bond formation via a radical pathway and tolerated a series of functional groups, such as chloro, m
Photoinduced, copper-catalyzed alkylation of amides with unactivated secondary alkyl halides at room temperature
Do, Hien-Quang,Bachman, Shoshana,Bissember, Alex C.,Peters, Jonas C.,Fu, Gregory C.
supporting information, p. 2162 - 2167 (2014/03/21)
The development of a mild and general method for the alkylation of amides with relatively unreactive alkyl halides (i.e., poor substrates for S N2 reactions) is an ongoing challenge in organic synthesis. We describe herein a versatile transition-metal-catalyzed approach: in particular, a photoinduced, copper-catalyzed monoalkylation of primary amides. A broad array of alkyl and aryl amides (as well as a lactam and a 2-oxazolidinone) couple with unactivated secondary (and hindered primary) alkyl bromides and iodides using a single set of comparatively simple and mild conditions: inexpensive CuI as the catalyst, no separate added ligand, and C-N bond formation at room temperature. The method is compatible with a variety of functional groups, such as an olefin, a carbamate, a thiophene, and a pyridine, and it has been applied to the synthesis of an opioid receptor antagonist. A range of mechanistic observations, including reactivity and stereochemical studies, are consistent with a coupling pathway that includes photoexcitation of a copper-amidate complex, followed by electron transfer to form an alkyl radical.
Copper-catalyzed intermolecular amidation and imidation of unactivated alkanes
Tran, Ba L.,Li, Bijie,Driess, Matthias,Hartwig, John F.
supporting information, p. 2555 - 2563 (2014/03/21)
We report a set of rare copper-catalyzed reactions of alkanes with simple amides, sulfonamides, and imides (i.e., benzamides, tosylamides, carbamates, and phthalimide) to form the corresponding N-alkyl products. The reactions lead to functionalization at secondary C-H bonds over tertiary C-H bonds and even occur at primary C-H bonds. [(phen)Cu(phth)] (1-phth) and [(phen)Cu(phth)2] (1-phth2), which are potential intermediates in the reaction, have been isolated and fully characterized. The stoichiometric reactions of 1-phth and 1-phth2 with alkanes, alkyl radicals, and radical probes were investigated to elucidate the mechanism of the amidation. The catalytic and stoichiometric reactions require both copper and tBuOOtBu for the generation of N-alkyl product. Neither 1-phth nor 1-phth2 reacted with excess cyclohexane at 100 C without tBuOOtBu. However, the reactions of 1-phth and 1-phth2 with tBuOOtBu afforded N-cyclohexylphthalimide (Cy-phth), N-methylphthalimide, and tert-butoxycyclohexane (Cy-OtBu) in approximate ratios of 70:20:30, respectively. Reactions with radical traps support the intermediacy of a tert-butoxy radical, which forms an alkyl radical intermediate. The intermediacy of an alkyl radical was evidenced by the catalytic reaction of cyclohexane with benzamide in the presence of CBr4, which formed exclusively bromocyclohexane. Furthermore, stoichiometric reactions of [(phen)Cu(phth)2] with tBuOOtBu and (Ph(Me)2CO) 2 at 100 C without cyclohexane afforded N-methylphthalimide (Me-phth) from β-Me scission of the alkoxy radicals to form a methyl radical. Separate reactions of cyclohexane and d12-cyclohexane with benzamide showed that the turnover-limiting step in the catalytic reaction is the C-H cleavage of cyclohexane by a tert-butoxy radical. These mechanistic data imply that the tert-butoxy radical reacts with the C-H bonds of alkanes, and the subsequent alkyl radical combines with 1-phth2 to form the corresponding N-alkyl imide product.
Pd(ii)-catalyzed decarboxylative cross-coupling of oxamic acids with potassium phenyltrifluoroborates under mild conditions
Li, Mingzong,Wang, Cong,Fang, Ping,Ge, Haibo
supporting information; experimental part, p. 6587 - 6589 (2011/06/25)
A novel Pd-catalyzed decarboxylative cross-coupling of oxamic acids with potassium phenyltrifluoroborates has been realized under mild reaction conditions. This method provides an efficient access to N-mono- or N,N-disubstituted benzamides and benzoates.
