2436-85-3Relevant academic research and scientific papers
Linear free energy relationships in the Bergman cyclization of 4-substituted-1,2-diethynylbenzenes
Choy,Kim,Ballestero,Artigas,Diez,Lichtenberger,Shapiro,Russell
, p. 6955 - 6958 (2000)
A series of 4-substituted-1,2-diethylnylbenzenes were prepared (1a-f) and subjected to Bergman cyclization. Bulk cyclization proceeded to produce the corresponding 2-substituted naphthalenes (2a-f) in good yields (59-78%). Kinetic experiments show a linear free energy relationship between the cyclization rate and the Hammett σ(m) substituent coefficient and the Swain-Lupton field and resonance parameters. (C) 2000 Elsevier Science Ltd.
Palladium-Catalyzed Cross-Coupling of Superbase-Generated C(sp3) Nucleophiles
Freure, Garrett P. R.,Lavertu, Jean-Danick E.,Newman, Stephen G.,Skrotzki, Eric A.
, p. 12258 - 12263 (2021/10/26)
A range of methods has been investigated recently for the arylation of weakly acidic C(sp3)-H bonds, primarily exploiting directed metalation with a transition metal catalyst or radical formation via hydrogen atom transfer. In this work, a classical base-mediated approach is taken, exploiting the ability of organometallic superbases to metalate very weakly acidic (pKa> 40) C-H bonds. Conditions are developed with eithern-BuLi/diamine orn-BuLi/KOtBu superbases to enable metalation to occur with high selectivity. Organolithium nucleophiles can be directly used in cross-coupling, or organozincs can be formed to enable reactions with functional group-dense organohalides.
Photoinduced Deaminative Borylation of Unreactive Aromatic Amines Enhanced by CO2
Shiozuka, Akira,Sekine, Kohei,Kuninobu, Yoichiro
supporting information, p. 4774 - 4778 (2021/06/28)
Herein, direct unreactive C-N borylation of aromatic amines by a photocatalyst was achieved. The C-N borylation of aromatic amines with bis(pinacolato)diboron (B2pin2) proceeded using a pyrene catalyst under light irradiation to afford desired borylated products and aminoborane as a byproduct. The yield of the borylated product improved under a CO2 atmosphere which probably reduced the inhibitory effect of aminoborane. Mechanistic studies suggested that the C-N bond cleavage and C-B bond formation proceeded via a concerted pathway.
Additive-freeN-methylation of amines with methanol over supported iridium catalyst
Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
, p. 3364 - 3375 (2021/06/06)
An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
Nickel-Catalyzed Amination of Aryl Chlorides with Amides
Li, Jinpeng,Huang, Changyu,Wen, Daheng,Zheng, Qingshu,Tu, Bo,Tu, Tao
supporting information, p. 687 - 691 (2021/01/09)
A nickel-catalyzed amination of aryl chlorides with diverse amides via C-N bond cleavage has been realized under mild conditions. A broad substrate scope with excellent functional group tolerance at a low catalyst loading makes the protocol powerful for synthesizing various aromatic amines. The aryl chlorides could selectively couple to the amino fragments rather than the carbonyl moieties of amides. Our protocol complements the conventional amination of aryl chlorides and expands the usage of inactive amides.
Iron-Catalyzed Oxidative C?C Cross-Coupling Reaction of Tertiary Anilines with Hydroxyarenes by Using Air as Sole Oxidant
Purtsas, Alexander,Kataeva, Olga,Kn?lker, Hans-Joachim
, p. 2499 - 2508 (2020/02/11)
A mild procedure for the oxidative C?C cross-coupling of tertiary anilines with phenols is described which provides the products generally in high yields and with excellent selectivity. The reaction is catalyzed by the hexadecafluorinated iron–phthalocyanine complex FePcF16 in the presence of substoichiometric amounts of methanesulfonic acid and ambient air as sole oxidant.
Expedient Synthesis of N-Methyl- and N-Alkylamines by Reductive Amination using Reusable Cobalt Oxide Nanoparticles
Senthamarai, Thirusangumurugan,Murugesan, Kathiravan,Natte, Kishore,Kalevaru, Narayana V.,Neumann, Helfried,Kamer, Paul C. J.,Jagadeesh, Rajenahally V.
, p. 1235 - 1240 (2018/02/09)
N-Methyl- and N-alkylamines represent important fine and bulk chemicals that are extensively used in both academic research and industrial production. Notably, these structural motifs are found in a large number of life-science molecules and play vital roles in regulating their activities. Therefore, the development of convenient and cost-effective methods for the synthesis and functionalization of amines by using earth-abundant metal-based catalysts is of scientific interest. In this regard, herein we report an expedient reductive amination process for the selective synthesis of N-methylated and N-alkylated amines by using nitrogen-doped, graphene-activated nanoscale Co3O4-based catalysts. Starting from inexpensive and easily accessible nitroarenes or amines and aqueous formaldehyde or aldehydes in the presence of formic acid, this cost-efficient reductive amination protocol allows the synthesis of various N-methyl- and N-alkylamines, amino acid derivatives, and existing drug molecules.
Heterogeneous Rhodium-Catalyzed Aerobic Oxidative Dehydrogenative Cross-Coupling: Nonsymmetrical Biaryl Amines
Matsumoto, Kenji,Yoshida, Masahiro,Shindo, Mitsuru
supporting information, p. 5272 - 5276 (2016/04/26)
The first heterogeneously catalyzed oxidative dehydrogenative cross-coupling of aryl amines is reported herein. 2-Naphthylamine analogues were reacted with various electron-rich arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions, thus affording nonsymmetrical biaryl amines in excellent yields with high selectivities. This reaction provides a mild, operationally simple, and efficient approach for the synthesis of biaryls which are important to pharmaceutical and materials chemistry. A jab-cross move: A heterogeneously catalyzed oxidative dehydrogenative cross-coupling of aryl amines is reported. Aryl amines were treated with various arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions to selectively afford cross-coupled products, and provides an efficient synthetic method for the preparation of nonsymmetrical biaryl amines by oxidative C-H activation.
C-O/C-H Coupling of Polyfluoroarenes with Aryl Carbamates by Cooperative Ni/Cu Catalysis
Wang, Yang,Wu, Song-Bai,Shi, Wen-Juan,Shi, Zhang-Jie
supporting information, p. 2548 - 2551 (2016/07/06)
Cross-coupling of polyfluoroarenes with aryl carbamates through the cleavage of both sp2 C-O and C-H bonds is reported. The reaction conditions are simple, and only transition-metal catalysts and ligands are essential. Mechanistic studies indicated that Ni catalyst played an important role in activating C-O bond, while the Cu one in activating C-H Bond. The developed system proved to be effective for cross-coupling of terminal alkynes with aryl carbamates.
6π/10π-Electrocyclization of ketene-iminium salts for the synthesis of substituted naphthylamines
Villedieu-Percheron, Emmanuelle,Catak, Saron,Zurwerra, Didier,Staiger, Roman,Lachia, Mathilde,De Mesmaeker, Alain
, p. 2446 - 2449 (2014/05/06)
An intramolecular 6π/10π-electrocyclization from ketene-iminium salts was developed for the preparation of naphthylamines. Various substituents on the nitrogen, on the aromatic ring, and on the olefin were studied. Tricyclic skeletons were obtained in few steps and good overall yields. The electrocyclization of ketene-iminium salts has been computationally explored by means of DFT calculations and their activation barriers were compared to the parent triene as well as the corresponding dienyl allenes and dienyl ketenes. Electrocyclizations for ketene-iminium salts were shown to be highly exergonic and have much smaller barriers to activation.
