- Preferential oxidative addition in palladium(0)-catalyzed suzuki cross-coupling reactions of dihaloarenes with arylboronic acids
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The study of Pd(0)-/t-Bu3P system as a powerful catalyst for the cross-coupling of n,m-dihaloarenes with 1 equiv of arylboronic acids is described. Our work demonstrated that the fate of the regenerated Pd(0) catalyst can be controlled when the appropriate ligand is employed. The results described here may lead to the development of new, efficient processes to conjugate polymers with controlled length which are potentially useful in molecular electronics. Copyright
- Dong, Cheng-Guo,Hu, Qiao-Sheng
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- Synthesis of fluoren-9-ones via palladium-catalyzed cyclocarbonylation of o-halobiaryls.
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The synthesis of various substituted fluoren-9-ones has been accomplished by a novel palladium-catalyzed cyclocarbonylation of o-halobiaryls. The cyclocarbonylation of 4'-substituted-2-iodobiphenyls produces very high yields of 2-substituted fluoren-9-ones bearing either electron-donating or electron-withdrawing substituents. 3'-Substituted 2-iodobiphenyls afford in excellent yields with good regioselectivity 3-substituted fluoren-9-ones. This chemistry has been successfully extended to polycyclic and heterocyclic fluorenones.
- Campo,Larock
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- Modular Tandem Mizoroki-Heck/Reductive Heck Reactions to Construct Fluorenes from Cyclic Diaryliodoniums
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Starting from cyclic diaryliodoniums and terminal alkenes, a diverse set of fluorenes is conveniently constructed. The reactions catalyzed by palladium undergo one conventional Mizoroki-Heck reaction and one reductive Heck reaction. The scope of alkenes is general, leading to 29 fluorenes which would expand the structural diversity of fluorene reservoir. (Figure presented.).
- Peng, Xiaopeng,Yang, Yang,Luo, Bingling,Wen, Shijun,Huang, Peng
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supporting information
p. 222 - 226
(2020/12/01)
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- Atmosphere-Controlled Palladium-Catalyzed Divergent Decarboxylative Cyclization of 2-Iodobiphenyls and α-Oxocarboxylic Acids
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A novel palladium-catalyzed divergent decarboxylative cyclization of 2-iodobiphenyls and α-oxocarboxylic acids utilizing the atmosphere as a controlled switch is reported. Under the protection of a nitrogen atmosphere, tribenzotropones are synthesized by a [4 + 3] decarboxylative cyclization. Employing a palladium/O2 system enables a [4 + 2] decarboxylative cyclization to assemble triphenylenes. Notably, preliminary mechanistic studies indicate that the formation of triphenylenes involves a double decarboxylation.
- Zhou, Liwei,Sun, Mingjie,Zhou, Fengru,Deng, Guobo,Yang, Yuan,Liang, Yun
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supporting information
p. 7150 - 7155
(2021/09/18)
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- Palladium-Catalyzed C-H Amination/[2 + 3] or [2 + 4] Cyclization via C(sp3or sp2)-H Activation
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This report describes a palladium-catalyzed Catellani reaction consisting of amination/[2 + 3] or [2 + 4] cyclization via a carboxylate ligand-exchange strategy. This method effectively activates ortho-substituents that avoid a second C-H palladation. The scope of substrates was broad, o-methyl-substituted iodoarenes were applied to the reaction smoothly, and o-phenyl-substituted iodoarenes can also be obtained by this method. In terms of mechanism, density functional theory calculations proved the sequence of the key five-membered aryl-norbornene-palladacycle intermediate formation and C(sp3 or sp2)-H activation.
- An, Yang,Ding, Ya-Nan,Gou, Xue-Ya,Li, Qiao,Li, Yuke,Liang, Yong-Min,Zhang, Xiao-Yan,Zhang, Zhe
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supporting information
p. 7961 - 7965
(2021/10/25)
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- Broad activity of diphenyleneiodonium analogues against Mycobacterium tuberculosis, malaria parasites and bacterial pathogens
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In this study, a structure-activity relationship (SAR) compound series based on the NDH-2 inhibitor diphenyleneiodonium (DPI) was synthesised. Compounds were evaluated primarily for in vitro efficacy against Gram-positive and Gram-negative bacteria, commonly responsible for nosocomial and community acquired infections. In addition, we also assessed the activity of these compounds against Mycobacterium tuberculosis (Tuberculosis) and Plasmodium spp. (Malaria). This led to the discovery of highly potent compounds active against bacterial pathogens and malaria parasites in the low nanomolar range, several of which were significantly less toxic to mammalian cells.
- Nguyen, Nghi,Wilson, Danny W.,Nagalingam, Gayathri,Triccas, James A.,Schneider, Elena K.,Li, Jian,Velkov, Tony,Baell, Jonathan
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p. 507 - 518
(2017/12/26)
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- Sequential Difunctionalization of 2-Iodobiphenyls by Exploiting the Reactivities of a Palladacycle and an Acyclic Arylpalladium Species
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A novel sequential difunctionalization reaction of 2-iodobiphenyl has been developed by exploiting the distinct reactivities of a palladacycle and an acyclic arylpalladium species. In this tandem reaction, an in situ formed dibenzopalladacyclopentadiene reacts selectively with an alkyl halide, after which the thus formed acyclic arylpalladium species selectively undergoes a Heck reaction with an alkene. This work demonstrates the strong relationship between the coordination mode of a transition metal complex and its reactivity, which could shed light on the mechanisms of other transition-metal-catalyzed reactions and offer the opportunity to develop other synthetically enabling organic transformations.
- Chen, Dushen,Shi, Guangfa,Jiang, Hang,Zhang, Yu,Zhang, Yanghui
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supporting information
p. 2130 - 2133
(2016/06/01)
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- Synthesis of Fluorenes Starting from 2-Iodobiphenyls and CH2Br2 through Palladium-Catalyzed Dual C-C Bond Formation
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A facile and efficient approach is developed for the synthesis of fluorene and its derivatives starting from 2-iodobiphenyls and CH2Br2. A range of fluorene derivatives can be synthesized under relatively mild conditions. The reaction proceeds via a tandem palladium-catalyzed dual C-C bond formation sequence through the key dibenzopalladacyclopentadiene intermediates, which are obtained from 2-iodobiphenyls through palladium-catalyzed C-H activation.
- Shi, Guangfa,Chen, Dushen,Jiang, Hang,Zhang, Yu,Zhang, Yanghui
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supporting information
p. 2958 - 2961
(2016/07/06)
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- Ni(cod)2/PCy3-catalyzed cross-coupling reactions of dihaloarenes with arylboronic acids
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The Ni(0)-catalyzed cross-coupling reactions of dihaloarenes with one equivalent of arylboronic acids is described. The Ni(cod)2/PCy 3 was identified as the best catalyst system to achieve a double cross-coupling reaction, likely via an efficient preferential oxidative addition. Georg Thieme Verlag Stuttgart New York.
- Dong, Cheng-Guo,Hu, Qiao-Sheng
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supporting information
p. 2121 - 2125
(2012/11/07)
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- 2'-Halobiphenyl-4-yl intermediates in the synthesis of angiotensin II antagonists
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A process for obtaining 2'-halo-4-methylbiphenyls is described, which comprises reacting 4-halotoluene with a 1,2-dihalobenzene in the presence of elemental metal such as magnesium, lithium or zinc, wherein 0 to 0.9 molar, particularly 0 to 0.2 molar excess of 4-halotoluene in regard to 1,2-dihalobenzene is used, and arised organometal intermediates are quenched by elemental halogen. In addition, the coupling of arised 2'-halo-4-methylbiphenyls with 2-(1-propyl)-4-methyl-6-(1'-methylbenzimidazole-2-il)benzimidazole to afford 3'-(2'-halo-biphenyl-4-ylmethyl)-1,7'-dimethyl-2'-propyl-1H,3'H-[2,5']bibenzoimidazolyl, which can be further converted to organometallic compound and said organometallic compound is further reacted with formic acid derivative, such as N,N-dimethylformamide, alkylformiate or carbon dioxide to obtain telmisartan, is also described. Further described is use of in line analytics for monitoring the aforementioned reactions.
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Page/Page column 9
(2009/10/01)
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- Catalyzed carbonylation in the synthesis of angiotensin ii antagonists
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One embodiment disclosed in the invention is the efficient synthesis of halogenated biaryl starting material via Grignard chemistry and the use thereof. Another embodiment of the invention is the reaction of catalyzed carbonylation of the 3'-(2'-halo-biphenyl-4-ylmethyl)-1,7'-dimethyl-2'-propyl-1H,3'H-[2,5']bibenzoimidazolyl (TLMH) using either gaseous carbon monoxide in a solvent mixture containing water; or formic acid salts optionally together with acetic acid in anhydrous solvent.
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Page/Page column 6-7
(2009/10/01)
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- Easily attachable and detachable ortho-directing agent for arylboronic acids in ruthenium-catalyzed aromatic C-H silylation
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(Chemical Equation Presented) o-C?H silylation of arylboronic acids has been achieved using 2-pyrazol-5-ylaniline as an orthodirecting agent, which was temporarily attached to the boronyl group via Ru-catalyzed silylation with hydrosilanes. Condensation products of arylboronic acids with2-pyrazol-5-ylaniline were prepared in situ and subjected to reaction w ith triorganosilanes in the presence of RuH2(CO)(PPh3) 3 at 135°C. Regioselective silylation at their ortho-positions proceeded in good yields for phenylboronic acids bearing para-substituents such as chloro, fluoro, methyl, methoxy, and trifluoromethyl groups. p-Methoxycarbonyl-substituted phenylboronic acid provided thecorresponding silylated product in moderate yield. m-Tolyl- and 2-napht hylboronic acids underwent silylation selectively at the less stericallyhindered ortho-positions. The silylated products were utilized in Suzuk i?Miyaura coupling, followed either by iodination with ICl or by Tamao oxidation to furnish iodine- or hydroxy-substituted biaryls.
- Ihara, Hideki,Suginome, Michinori
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supporting information; experimental part
p. 7502 - 7503
(2009/10/16)
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- Radiosynthesis of [tetrazoyl-11C]irbesartan, a non-peptidic angiotensin II antagonist
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With the aim of visualizing myocardial angiotensin II receptors (AT1 subtypes), [tetrazoyl-11C]2-n-butyl-1-[(2'-(1H-tetrazol-5-yl)-1,1'-biphenyl-4-yl)methyl] - 4-spirocyclo-pentane-2-imidazoline-5-one ([tetrazoyl-11C]irbesartan (SR47436/BMS-186295)) 11 was synthesized in one pot in four steps from [11C]hydrogen cyanide. The labelling process which yielded [tetrazoyl-11C]irbesartan is described in detail and could be applied to the labelling of other ligands which possess the (1H-tetrazol-5-yl) moiety. Positron emission tomography (PET) studies were performed in dogs. Heart, lung and blood time-activity curves did not change. Therefore this new radioligand is not suitable for studying myocardial angiotensin II receptors with PET.
- Penchant,Demphel,Hinnen,Crouzel
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p. 747 - 752
(2007/10/03)
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- Benzo-fused lactams promote release of growth hormone
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There are disclosed certain novel compounds identified as benzo-fused lactams which promote the release of growth hormone in humans and animals. This property can be utilized to promote the growth of food animals to render the production of edible meat products more efficient, and in humans, to increase the stature of those afflicted with a lack of a normal secretion of natural growth hormone. The compounds are prepared by substitution of an amino-lactam with a substituted amide function. Growth promoting compositions containing such bezno-fused lactams as the active ingredient thereof are also disclosed. STR1 where L is STR2
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- Helically chiral thia- and diselena-quinquephenylophanes
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Helically chiral thia- and diselena-quinquephenylophanes have been synthesized starting from suitable benzene derivatives via an 8-step synthesis path.Helical thiaquinquephenylophane 9 was obtained from bis(bromomethyl)quinquephenyl 8 in cyclisation with thioacetamide under high-dilution conditions in 10percent yield.The corresponding diselenaquinquephenylophane was obtained in 17percent yield by using KSeCN and reduction.The M- and P-enantiomers of the thiaphane were separated by HPLC using the Okamoto resin.The CD and UV spectra of the pure M- and P-enantiomers of the thiaphane were recorded.X-Ray structure analyses of the racemic crystals were performed for both compounds.Unit-cell parameters: 9, a = 10.952(1), b = 11.896(2), c = 9.804(1) Angstroem, α = 104.19(1), β = 111.71(1), γ = 80.19(1) deg, V = 1146.0(3) Angstroem3; 10, a = 10.304(2), b = 15.204(4), c = 9.128(1) Angstroem, α = 105.08(2), β = 113.72(1), γ = 93.41(2) deg, V = 1242.2(5) Angstroem3.In addition, a dimeric selena-bridged quinduephenylophane was observed, and its presence confirmed by FAB-MS and 77Se NMR spectroscopy.
- Airola, Karri,Bartam, Stefan,Rissanen, Kari
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p. 895 - 900
(2007/10/02)
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