- Electrochemical Decarboxylative Cyclization of α-Amino-Oxy Acids to Access Phenanthridine Derivatives
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Phenanthridines are a class of useful heterocycles in the field of drug development. In this work, a method via electrochemical decarboxylative cyclization of α-amino-oxy acids to access phenanthridine derivatives was developed. This reaction proceeded th
- Zhan, Yanling,Dai, Changhui,Zhu, Zitong,Liu, Ping,Sun, Peipei
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supporting information
(2022/02/07)
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- Base-Free Suzuki–Miyaura Coupling Reaction Using Palladium(II) Supported Catalyst in Water
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Abstract: The carbon–carbon bond formation via Suzuki–Miyaura reaction was performed in water as green solvent. Pd(OAc)2(PPh3)2 supported on magnesium hydroxide and cerium carbonate hydroxide composite was prepared and characterized by various techniques. The cross-coupling reaction of aryl halides carried out in water using mild conditions. The effects of temperature, solvents, the amount of catalyst and leaving groups were studied to find the optimization conditions for cross-coupling reaction. Various aryl halides were smoothly transformed into the biaryls in good yields. In addition, the catalyst also exhibited stability and catalytic performance in the cross-coupling of aryl halides. Graphical Abstract: [Figure not available: see fulltext.] A new approach is developed for carbon–carbon bond formation via Suzuki–Miyaura reaction.2 Pd(OAc)2(PPh3)2?supported on mixed magnesium hydroxide and cerium carbonate hydroxide were prepared and characterized by XRD, XPS, SEM–EDX techniques. The cross-coupling reaction of aryl halides can be carried out in water and under mild conditions (80 °C).
- Tomar, Ravi,Singh, Nidhi,Kumar, Neeraj,Tomar, Vartika,Chandra, Ramesh
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- Suzuki–Miyaura Coupling of (Hetero)Aryl Sulfones: Complementary Reactivity Enables Iterative Polyaryl Synthesis
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Ideal organic syntheses involve the rapid construction of C?C bonds, with minimal use of functional group interconversions. The Suzuki–Miyaura cross-coupling (SMC) is a powerful way to form biaryl linkages, but the relatively similar reactivity of electrophilic partners makes iterative syntheses involving more than two sequential coupling events difficult to achieve without additional manipulations. Here we introduce (hetero)aryl sulfones as electrophilic coupling partners for the SMC reaction, which display an intermediate reactivity between those of typical aryl (pseudo)halides and nitroarenes. The new complementary reactivity allows for rapid sequential cross-coupling of arenes bearing chloride, sulfone and nitro leaving groups, affording non-symmetric ter- and quateraryls in only 2 or 3 steps, respectively. The SMC reactivity of (hetero)aryl sulfones is demonstrated in over 30 examples. Mechanistic experiments and DFT calculations are consistent with oxidative addition into the sulfone C?S bond as the turnover-limiting step. The further development of electrophilic cross-coupling partners with complementary reactivity may open new possibilities for divergent iterative synthesis starting from small pools of polyfunctionalized arenes.
- Chatelain, Paul,Sau, Abhijit,Rowley, Christopher N.,Moran, Joseph
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supporting information
p. 14959 - 14963
(2019/11/05)
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- Expedient Preparation of Aryllithium and Arylzinc Reagents from Aryl Chlorides Using Lithium 4,4′-Di- tert -Butylbiphenylide and Zinc(II) Chloride
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We report an efficient method for the preparation of aryllithium and zinc reagents from inexpensive and readily available aryl chlorides by using lithium 4,4′-di-tert-butylbiphenylide (LiDBB) as a lithiation reagent. The resulting organometallic reagents underwent subsequent reactions with a variety of electrophiles, such as an aldehydes, DMF, PhSSO2Ph, TsCN, an aryl halide, or an acid chloride (through Pd-catalyzed cross-coupling). Aryl chlorides bearing substituents, including methoxy, 3,4-methylenedioxy, fluoride, TMS, OTMS, NMe2, acetal, and ketal, were shown to be appropriate substrates. Interestingly, aryl chlorides containing a formyl group could also be used, provided that the formyl group was temporarily converted into an α-amino alkoxide by using the lithium amide of N,N,N′-trimethylethylenediamine (LiTMDA). The presence of a hydroxyl group was also tolerated when it was deprotonated with n-BuLi prior to the addition of LiDBB.
- Shen, Zhi-Liang,Sommer, Korbinian,Knochel, Paul
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p. 2617 - 2630
(2015/09/01)
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- Gold-catalyzed 6-exo-dig cycloisomerization: A versatile approach to functionalized phenanthrenes
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A novel gold-catalyzed 6-exo-dig cycloisomerization of o-propargylbiaryls has been developed that provides ready access to functionalized phenanthrenes in largely good to excellent yields. Notable features of this method are readily available starting materials, mild reaction conditions, and broad substrate scope. Golden cat: A novel gold-catalyzed 6-exo-dig cycloisomerization of o-propargylbiaryls has been developed that provides ready access to functionalized phenanthrenes in largely good to excellent yields. Notable features of this method are readily available starting materials, mild reaction conditions, and broad substrate scope.
- Shu, Chao,Li, Long,Chen, Cheng-Bin,Shen, Hong-Cheng,Ye, Long-Wu
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supporting information
p. 1525 - 1529
(2014/06/09)
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- Synthesis of phenanthrenes through copper-catalyzed cross-Coupling of N-tosylhydrazones with terminal alkynes
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A novel protocol for the synthesis of phenanthrenes through the copper-catalyzed reaction of aromatic tosylhydrazones with terminal alkynes is explored. The reaction proceeds via the formation of an allene intermediate and subsequent six-π-electron cyclization-isomerization, affording phenanthrene derivatives in good yields. The transformation can be performed in two ways:(1)with Ntosylhydrazones derived from [1,1'-biphenyl]-2-carbaldehydes and terminal alkynes as the starting materials and(2)with Ntosylhydrazones derived from aromatic aldehydes and 2-alkynyl biphenyls as the starting materials. This new phenanthrene synthesis uses readily available starting materials and a cheap copper catalyst and has a wide range of functional group compatibility.
- Hossain, Mohammad Lokman,Ye, Fei,Liu, Zhenxing,Xia, Ying,Shi, Yi,Zhou, Lei,Zhang, Yan,Wang, Jianbo
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p. 8689 - 8699
(2015/01/08)
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- Microwave-assisted syntheses of N-heterocycles using alkenone-, alkynone- and aryl-carbonyl O-phenyl oximes: Formal synthesis of neocryptolepine
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(Chemical Equation Presented) This research aimed to provide a new and "clean" synthetic method that would enable both known and novel N-heterocycles to be prepared efficiently. O-Phenyl oximes were found to be excellent precursors for iminyl radicals with a variety of acceptor side chains. Dihyropyrroles were made in good yields from O-phenyl oximes containing pent-4-ene acceptors. The analogous process with a hex-5-enyl acceptor did not yield a dihydropyridine, probably because the 6-exo-trig ring closure of the iminyl radical was too slow to compete with H-atom abstraction. The iminyl radical from a precursor with a pent-4-yne type side chain underwent ring closure followed by rearrangement to afford a pyrrole derivative. Suitably substituted iminyl radicals ring closed readily onto aromatic acceptors, thus enabling several polycyclic systems to be accessed. Quinolines were made from 3-phenylpropanones via their O-phenyl oximes. Syntheses of phenanthridines starting from 2-formylbiphenyls were particularly efficient, and this approach enabled the natural product trisphaeridine to be made. Starting from 2-phenylnicotinaldehyde derivatives, ring closures of the derived iminyl radicals onto the phenyl rings yielded benzo[h][1,6]naphthyridines. Similarly, ring closure onto a phenyl ring from a benzothiophene-based iminyl yielded a benzo[b-]thieno[2,3-c]quinoline. By way of contrast, iminyl radical ring closure onto pyridine rings was not observed. However, iminyl radicals did cyclize onto indoles, enabling indolopyridines to be prepared. The latter route was exploited in a short formal synthesis of neocryptolepine starting from 2-((1H-indol-3-yl)methyl)cyclohexanone.
- Portela-Cubillo, Fernando,Scott, Jackie S.,Walton, John C.
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p. 5558 - 5565
(2008/12/20)
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- 2-(Biarylalkyl)amino-3-(cyanoalkanoylamino)pyridine derivatives
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Compounds disclosed herein are bradykinin B1 antagonist compounds useful in the treatment or prevention of symptoms such as pain and inflammation associated with the bradykinin B1 pathway.
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Page/Page column 15
(2010/02/05)
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- Preparation of ortho-Aryl-benzaldehyde Derivatives via Free-Radical ipso-Substitution of an Amidomethyl Group
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Preparation of 2-biarylcarbaldehydes using an intramolecular free-radical ipso-substitution is described. The two aryl moieties to be coupled are pre-associated using a glycolamide derivative. An unusual amidomethyl leaving group was successfully employed in this process.
- Giraud, Luc,Lacote, Emmanuel,Renaud, Philippe
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p. 2148 - 2156
(2007/10/03)
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