- Nickel-catalyzed reductive amidation of aryl-triazine ethers
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The reaction of activated phenolic compounds, 2,4,6-triaryloxy-1,3,5-triazine (aryl-triazine ethers), with various isocyanates or carbodiimides in the presence of a nickel pre-catalyst resulted in the synthesis of aryl amides in good to excellent yields.
- Heravi, Majid M.,Panahi, Farhad,Iranpoor, Nasser
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supporting information
p. 1992 - 1995
(2020/02/22)
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- Integration of co2 reduction with subsequent carbonylation: Towards extending chemical utilization of co2
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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.
- Lang, Xian-Dong,He, Liang-Nian
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- Quantitative investigation of C-H?π and other intermolecular interactions in a series of crystalline: N -(substituted phenyl)-2-naphthamide derivatives
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In this study, we have investigated the nature and characteristics of different intermolecular interactions present in a series of seven N-(substituted phenyl)-2-naphthamides. The seven structures comprise 2-naphthyl ring systems linked by amide bridges to N-bound phenyl 1, or substituted benzene rings 3-7, or in the case of 2, a cyclohexane ring. A common feature of the crystal packing for all but the o-nitro derivative 7 is the presence of a strong intermolecular N-H?O interaction. In the case of 7, the possibility of such an interaction is obviated by the formation of an intramolecular N-H?O hydrogen bond. An additional feature of the crystal packing for 1-6 is the significant roles that C-H?π contacts play in generating three-dimensional networks. In contrast for 7, the intramolecular N-H?O hydrogen bond precludes the formation of molecular chains but the planar nature of this molecule allows significant π?π stacking interactions to stabilize the packing.
- Shukla, Rahul,Saeed, Aamer,Simpson, Jim,Chopra, Deepak
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p. 5473 - 5491
(2017/09/26)
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- Ni-catalyzed direct reductive amidation via C-O bond cleavage
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A novel Ni-catalyzed reductive amidation of C(sp2)-O and C(sp3)-O electrophiles with isocyanates is described. This umpolung reaction allows for an unconventional preparation of benzamides using simple starting materials and easy-to-handle Ni catalysts.
- Correa, Arkaitz,Martin, Ruben
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supporting information
p. 7253 - 7256
(2014/06/09)
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- Photoinduced, copper-catalyzed alkylation of amides with unactivated secondary alkyl halides at room temperature
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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.
- Do, Hien-Quang,Bachman, Shoshana,Bissember, Alex C.,Peters, Jonas C.,Fu, Gregory C.
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supporting information
p. 2162 - 2167
(2014/03/21)
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- Are Aroylnitrenes Ground-State Singlets? Photochemistry of β-Naphtoyl Azide
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Both direct-irradiation and triplet-sensitized photolyses of β-naphtoyl azide (BNA) give nitrene-derived products indicative of reaction only from the singlet state of β-naphtoylnitrene (BNN).The triplet nitrene is not detected in chemical trapping or spectroscopic experiments, which readily reveal related intermediates.The results require that the energy of singlet BNN be very close to or below the energy of triplet BNN.The data are most consistent with a singlet ground state for BNN.A qualitative perturbation molecular orbital approach is used for this surprising finding.
- Autrey, Tom,Schuster, Gary B.
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p. 5814 - 5820
(2007/10/02)
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