- Microwave synthesis of charge-compensated dodecaborates bearing exohedral boron-phosphorus connectivities
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Solution pyrolysis of arylphosphonium salts of B12H122?,1, utilizing microwave heating provided charge-compensated monophosphine dodecaborate derivatives of general formula B12H11(PPhnR3-n)? (n = 1, R = Me; n = 2, R = Me, Et) in high yield. The resulting anions B12H11(PPh2Me)? (2), B12H11(PPhMe2)? (3), and B12H11(PPh2Et)? (4) were characterized by 11B, 1H, 13C, and 31P NMR spectroscopy, and by negative mode ESI-TOF mass spectrometry. A single-crystal X-ray diffraction study of [Ph3PMe]2 confirmed an icosahedral boron cluster fragment appended by a PPh2Me moiety through a P-B bond.
- Dopke, Joel A.,Lincoln, Zachary S.,Blazejewski, Jacob,Staples, Richard J.,Lee, Mark E.
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- GENERATION, TRAPPING AND FATE OF ALKYLIDENECARBENE-IODONIUM YLIDES FROM THE ADDITION OF NaN3 TO ALKYNYLPHENYLIODONIUM TOSYLATES
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Addition of NaN3 to RCCIPh(1+)*OTs(1-) results in novel alkylidenecarbene-iodonium ylides, 5, R(N3)C=C=IPh, that by either protonation, ylide transfer or insertion of the derived carbene R(N3)C=C: give unique functionalized vinyl azides.
- Kitamura, Tsugio,Stang, Peter J.
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- Gold-catalyzed synthesis of iodofulvenes
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We report the gold-catalyzed synthesis of highly functionalized iodofulvenes from iododialkynes under mild conditions. The catalytic cycle involves the formation of gold acetylides and vinylgold intermediates. These intermediates can then undergo an unprecedented iodine/gold exchange. This new pathway for catalyst transfer in dual gold catalysis opens up the possibility of highly regioselective transformations directed by the gold in the organogold intermediates. The resulting products are well suited for further metal-mediated coupling reactions, allowing the synthesis of extended π-systems. Iodine/gold exchange: A gold-catalyzed iodine transfer allows the efficient synthesis of benzofulvenes with iodo substituents on the fulvene core (see scheme). The new dual-activation catalysts are efficient catalysts for this new type of cycloisomerization. Copyright
- Noesel, Pascal,Lauterbach, Tobias,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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- Stereoselective synthesis of (Z)-enethiols and their derivatives: Vinylic SN2 reaction of (E)-alkenyl(phenyl)-λ3-iodanes with thioamides
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(Equation presented) Exposure of (E)-β-alkylvinyl(phenyl)-λ3-iodanes to thioamides in dichloromethane at room temperature was found to result in a bimolecular nucleophilic substitution (SN2) at the vinylic carbon atom to give inverted (Z)-enethiols and/or (Z)-S-vinylthioimidonium salts. Vinylic SN2 reactions with thioureas are also discussed.
- Ochiai, Masahito,Yamamoto, Shinji,Suefuji, Takashi,Chen, Da-Wei
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- (Diacetoxyiodo)benzene-Mediated Transition-Metal-Free Amination of C(sp3)-H Bonds Adjacent to Heteroatoms with Azoles: Synthesis of N-Alkylated Azoles
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A novel PhI(OAc) 2 -mediated cross-dehydrogenative coupling reaction of α-C(sp 3)-H bonds adjacent to a hetero atom with various azoles has been developed, which provides an alternative method for constructing C-N bonds with high atom efficiency. This new protocol requires no metal catalyst and it provides ready access to a wide range of N-alkylated azole derivatives in moderate to excellent yields by using commercially available PhI(OAc) 2 as the sole oxidant. Furthermore, the method is effective on a gram scale, which highlights the practicality of this transformation. The result of radical-captured experiments indicated that the transformation might involve a free-radical pathway.
- Sun, Bin,Yan, Zhiyang,Jin, Can,Su, Weike
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- KINETICS AND MECHANISM OF IODODESTANNYLATION OF STANNATRANES
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A detailed kinetic study of iododestannylation of phenylstannatranes is reported.Reaction rates were compared with reference systems PhSnBu3, PhSn(OMe)3.No evidence was found for iodide catalysis.The reaction is interpreted as involving rate determining Sn-C bond fission.Rates for the stannatranes are some seven times greater than those for PhSn(OMe)3 indicative of increased Sn-N coordination in the transition state.Salt effects were significantly smaller for the stannatranes commeasurate with decreased charge on the electrofugal tin.For PhSn(OMe)3, the reaction was followed in the absence of iodide ion, enabling the evaluation of the association constant for the species +I- formed during the reaction.
- Ravenscroft, M. D.,Roberts, R. M. G.
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- Remote Para-C-H Acetoxylation of Electron-Deficient Arenes
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One formidable challenge in sp2 C-H activation is how to achieve high para selectivity on electron-deficient arenes because such site selectivity is disfavored by the electronic bias induced by the electron-withdrawing groups. The first highly selective para-C-H acetoxylation of various benzoic acids using a nitrile-based template was realized. Removal of the template leads to para-hydroxylated benzoic acids, which are versatile intermediates for a wide range of synthetically useful transformations.
- Li, Minghong,Shang, Ming,Xu, Hui,Wang, Xing,Dai, Hui-Xiong,Yu, Jin-Quan
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- Preparation of Bis(arylthio)iodobenzene and Reaction with 1-Alkynes. A Novel Route to 1,2-Bis(arylthio)alkenes
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The in situ reaction of a novel hypervalent iodine reagent 2b having an arylthio ligand, prepared from phenyliodine diacetate and 2,3,5,6-tetrafluorothiophenol 1b in pyridine, with 1-alkynes 3 gave 1,2-bis(arylthio)alkenes 4 in good yields.
- Kita, Yasuyuki,Okuno, Takayuki,Tohma, Hirofumi,Akai, Shuji,Matsumoto, Keita
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- Reactions of Unsaturated Compounds with Iodine and Bromine on γ-Alumina
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Iodine reacts with a diverse group of unsaturated substrates in the presence of dehydrated alumina.Aromatic substrates, for example, are iodinated at room temperature by electrophilic aromatic substitution.The yields of the iodinated products can be improved dramatically by running the reaction at 110 deg C.Aniline, even at 100 deg C, is unreactive, presumably because its nitrogen lone pair is complexed to surface aluminum cation or protons.Alkenes react readily with HI, formed in the reaction of surface hydroxyls with I2, to form alkyl iodides by an ionic mechanism involving carbocations.This is an excellent method for the synthesis of alkyl iodides from alkenes.Alkynes, on the other hand, add I2 (stereospecific, anti) under very mild conditions to form vinyl diiodides in excellent yield.The behavior of Br2 with cyclohexene on alumina is considerably different than that of I2 withcyclohexene.Two products are formed: trans-1,2-dibromocyclohexane (1), which is formed in solution during workup, and trans-1-bromo-2-chlorocyclohexane (2), which is formed on the surface.The chlorine in 2 arise from intrinsic chloride already on the alumina and CCl4, the solvent used to adsorb Br2 onto alumina.Further experiments demonstrate that cyclohexene undergoes intergranular hopping, but that Br2 does not.
- Pagni, Richard M.,Kabalka, George W.,Boothe, Richard,Gaetano, Kevan,Stewart, Lyman J.,et al.
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- On the mechanism of photoinduced addition of acetonitrile to phosphonium-iodonium ylides
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Recently, a novel photochemical reaction of pseudocycloaddition of nitriles to mixed phosphonium-iodonium ylides 1 was found. Nitriles R1CN give corresponding oxazoles (2) with a high yield, with PhI (3) being a leaving group. The mechanism of the photoinduced cycloaddition of acetonitrile to mixed phosphonium-iodonium ylide 1 was studied by steady-state and time-resolved methods with resolution from 10 ns to 20 μs. The formation of photolysis products, substituted oxazole 2, and phosphonium salt 4, occurs in parallel reactions. The primary photochemical processes for the formation of 2 and 4 are the heterolytic and homolytic C-I+Ph bond cleavage in the excited singlet state of 1, respectively. Three transient species with lifetimes on microsecond and millisecond time scales were observed. The mechanism of the formation of major and minor products of the photolysis was suggested. Addition of water to the reaction mixture in acetonitrile changes the ratio of the products in favor of the phosphonium salt formation. The effect of water was accounted for by the acid catalysis of the homolytic C-I+Ph bond cleavage and the acceleration of the salt formation. Copyright
- Nekipelova, Tatiana D.,Kuzmin, Vladimir A.,Matveeva, Elena D.,Gleiter, Rolf,Zefirov, Nikolay S.
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- Syntheses of (1,1-Dihydroperfluoroalkyl)aryliodonium Triflates and Their Analogues
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(1,1-Dihydroperfluoroalkyl)phenyl- and -p-fluorophenyliodonium triflates 2 and 3 were synthesized by the reaction of 1-bis(trifluoroacetoxy)iodo-1,1-dihydroperfluoroalkanes 1 with triflic acid and benzene or fluorobenzene in 1,1,2-trichloro-trifluoroethane.The use of fluorosulfonic acid and sulfuric acid instead of triflic acid afforded (1,1-dihydroperfluoroalkyl)phenyliodonium fluorosulfonate 4 and sulfate 5, respectively.Similarly, (1,1,ω-trihydroperfluoroalkyl)phenyliodonium triflate 7 and 1,1,5,5-tetrahydroperfluoropentane-1,5-bisphenyliodonium triflate 9 were synthesized.
- Unemoto, Teruo,Gotoh, Yoshihiko
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- Reverse Halogenation Using Supported Copper(I) Iodide
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Alumina and charcoal supported copper(I) iodide reagents can be used to convert bromo- and chloro-benzenes into iodobenzenes with no back attack by bromide or chloride.
- Clark, James H.,Jones, Craig W.
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- Radiolysis of Solutions of Diphenyliodonium and Triphenylsulfonium Hexafluorophosphates in Various Solvents
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The radiolysis of solutions of Ph2IPF6 and Ph3SPF6 was undertaken in various kinds of solvents such as alcohols, ethers, acetone, acetonitrile, and dichloromethane.The salts decompose through one-electron reduction in all of the solvents except dichloromethane.The α-hydroxyalkyl and α-alkoxyalkyl radicals derived from the oxygen-containing solvents are oxidized by Ph2IPF6 to initiate a chain reaction.The kinetic chain length depends on the oxidation potentials of the radicals.In dichloromethane, which is an electron scavenger, the decomposition of the salts is much less pronounced than in other solvents.
- Ma, Xiao-Hua,Yamamoto, Yukio,Hayashi, Koichiro
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- Migratory insertion and reductive coupling of tetraarylruthenium(IV) complexes
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Tetraarylruthenium(IV) complexes have been synthesized and their migratory insertion, reductive coupling, and bromination reactions investigated. Treatment of [Ru(acac)3] (acac- = acetylacetonate) with RMgBr, followed by column chromatography in air afforded the tetraaryl complexes [RuR4] (R = 2,5-dimethylphenyl (R1); 4-methoxy-2-methylphenyl (R2)). Oxidation of [RuR24] with AgBF4 gave the Ru(V) complex [RuVR24](BF4), which has a measured μeff of 1.8 μB. [RuR4] and can catalyze the oxidation of methyl p-tolyl sulfide with PhIO. Reaction of [RuR24] with PhICl2 led to C-C reductive coupling and the formation of the Ru(II) η6-biaryl complex [(η6-R2-R2)RuCl2]2 (1). Treatment of [RuR14] with excess NO gave the tetranuclear Ru(II) aryl-N-nitrosohydroxylaminato complex [RuR1(N){κ2-O,O′-ON(R1)NO}(μ-NO2)]4 (2). Bromination of [RuR14] with N-bromosuccinimide resulted in formation of [RuR′4] (R′ = 4-bromo-2,5-dimethylphenyl) (3). The crystal structures of [RuR24], [RuR24](BF4), and 1-3 have been determined.
- So, Shiu-Chun,Cheung, Wai-Man,Wang, Guo-Cang,Kwan Huang, Enrique,Lau, Man-Kit,Zhang, Qian-Feng,Sung, Herman H.-Y.,Williams, Ian D.,Leung, Wa-Hung
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- The [closo-B12H11-1-IAr]- zwitterion as a precursor to monosubstituted derivatives of [closo-B12H12]2-
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Reactions of [closo-B12H12]2- with ArI(OAc)2 in aqueous AcOH in the presence of [NEt4]+ or [NHEt3]+ give [closo-B12H11-1-IAr]- (1) in 74-95% yield as a white precipitate. The zwitterions decompose in CD3CN solutions with rates k = 3.30 ± 0.04 × 10-4 s-1 (Ar = Ph, 1a[NEt4]) and k = 1.96 ± 0.01 × 10-4 s-1 (Ar = C6H4OMe-4, 1b[NEt4]) at 0 °C. Reactions of the zwitterion with Me2NCHS and pyridine gave the corresponding products [closo-B12H11-1-SCHNMe2]- (2) and [closo-B12H11-1-NC5H5]- (3) isolated in 25-27% and up to 44% yield, respectively. The former anion is a protected thiol derivative, which was transformed to the sulfonium derivative [closo-B12H11-1-S(CH2)5]- (8). The molecular structure and spectroscopic properties of pyridinium zwitterion 3 were analyzed experimentally and computationally (B3LYP), and results compared with those for the [closo-B10H9-1-NC5H5]- (4) analog. Mechanisms of formation of 2-4 from appropriate aryliodonium zwitterions were analyzed with the M062x computational method.
- Tokarz, Pawe?,Kaszyński, Piotr,Domaga?a, S?awomir,Wo?niak, Krzysztof
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- Iron-mediated desulphurization approach: synthesis of cyanamides and their conversions
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The iron-mediated efficient multi-component method has been demonstrated for the synthesis of substituted cyanamides from isothiocyanates under mild reaction conditions. Subsequent nucleophilic addition and desulfurization are involved in this proposed synthetic methodology. All the reactions are rapid, facile, and accomplished at room temperature. A variety of substrates readily underwent the optimized reaction conditions to provide their respective target products in good to excellent yields. Furthermore, we have confirmed that no other by-products could be identified during our experimental reaction process. Graphical abstract: Iron-mediated efficient multi-component method has been demonstrated for the synthesis of substituted cyanamides from isothiocyanates under mild reaction conditions. Subsequent nucleophilic addition and desulfurization are involved in this proposed synthetic methodology.[Figure not available: see fulltext.].
- Nannapaneni, Madhavi,Pendem, Venkata Bhavanarushi,Tamminana, Ramana
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- Sulfated polyborate-H2O assisted tunable activation of N-iodosuccinimide for expeditious mono and diiodination of arenes
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Owing to both Lewis and Bronsted acid active sites on sulfated polyborate under homogenous conditions, we were keen on developing iodination protocol of arenes that can meet the requirement of regioselectivity and higher yield. The sulfated polyborate activates N-iodosuccinimide for mono iodination of highly activated substrates viz. phenols, anilines under anhydrous condition. Water tunes sulfated polyborate to generate more Bronsted acid sites resulting in rapid activation of NIS for diiodination. The protocol was equally applicable to diiodination of 4-hydroxyphenylacetic acid to synthesize 4-hydroxy-3,5-diiodophenylacetic acid, an intermediate of tiratricol, a thyroid treatment drug. This protocol was further integrated via one-pot sequential iodination and Sonogashira coupling to synthesize aryl acetylenes, building blocks for the synthesis of a variety of specialty chemicals, API, and natural products.
- Misal, Balu,Palav, Amey,Ganwir, Prerna,Chaturbhuj, Ganesh
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supporting information
(2021/05/26)
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- NCBSI/KI: A Reagent System for Iodination of Aromatics through in Situ Generation of I-Cl
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In situ iodine monochloride (I-Cl) generation followed by iodination of aromatics using NCBSI/KI system has been developed. The NCBSI reagent requires no activation due to longer bond length, lower bond dissociation energy, and higher absolute charge density on nitrogen. The system is adequate for mono- and diiodination of a wide range of moderate to highly activated arenes with good yield and purity. Moreover, the precursor N-(benzenesulfonyl)benzenesulfonamide can be recovered and transformed to NCBSI, making the protocol eco-friendly and cost-effective.
- Palav, Amey,Misal, Balu,Chaturbhuj, Ganesh
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p. 12467 - 12474
(2021/08/24)
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- A convenient synthetic approach to a novel class of aryldifluoromethyl pyrimidine derivatives containing strobilurin motif as insecticidal agents
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A series of aryldifluoromethyl pyrimidine compounds containing strobilurin were synthesized through bioelectronic isometric design with azoxystrobin as the lead compound and a convenient approach to aryldifluoromethylpyrimidine intermediates was developed, which features mild reaction conditions and simple operation. The title compounds and aryldifluoromethylpyrimidine intermediates were characterized by NMR and HRMS. Both 7c and 7l of the preliminary screening tests showed 100% inhibition against Mythimna separata at 100 mg/L. At 20 mg/L, the lethal rate of 7l against Mythimna separata can be up to 80%.
- Cai, Zengfei,Cao, Yangyang,Du, Xiaohua,Hao, Shulin,Zhang, Wenliang
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supporting information
(2021/10/07)
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- Efficient Pd(ii)-catalyzed regioselectiveortho-halogenation of arylcyanamides
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Regioselectiveortho-halogenation of arylcyanamides using a Pd(ii) catalyst has been established under mild reaction conditions. Either electron-donating or electron-withdrawing groups readily carried out the reaction and produced final products in moderate to good yields. Based on the experimental work, we have confirmed that this method does not undergo a free radical mechanism. Furthermore, we have also attempted this method for practical utility purposes.
- Alam, M. Mujahid,Boddapati, S. N. M.,Bollikolla, Hari Babu,Gugulothu, Sailaja,Tamminana, Ramana,Varala, Ravi
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supporting information
p. 17176 - 17182
(2021/10/04)
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- Palladium-Catalyzed Decarbonylative Iodination of Aryl Carboxylic Acids Enabled by Ligand-Assisted Halide Exchange
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We report an efficient and broadly applicable palladium-catalyzed iodination of inexpensive and abundant aryl and vinyl carboxylic acids via in situ activation to the acid chloride and formation of a phosphonium salt. The use of 1-iodobutane as iodide source in combination with a base and a deoxychlorinating reagent gives access to a wide range of aryl and vinyl iodides under Pd/Xantphos catalysis, including complex drug-like scaffolds. Stoichiometric experiments and kinetic analysis suggest a unique mechanism involving C?P reductive elimination to form the Xantphos phosphonium chloride, which subsequently initiates an unusual halogen exchange by outer sphere nucleophilic substitution.
- Boehm, Philip,Cacherat, Bastien,Lee, Yong Ho,Martini, Tristano,Morandi, Bill
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supporting information
p. 17211 - 17217
(2021/07/02)
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- Synthesis of biaryl compounds via Suzuki homocoupling reactions catalyzed by metal organic frameworks encapsulated with palladium nanoparticles
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Heterogeneous homocoupling reactions of phenylboronic acids were greatly accelerated via Suzuki homocoupling reactions. In this work, a tandem route was designed which firstly one part of phenylboronic acids reacted with iodine to form iodobenzenes, then another part of phenylboronic acids coupled with iodobenzenes to produce biaryl compounds. The tandem reaction were catalyzed by a bifunctional heterogeneous catalyst of metal organic frameworks encapsulated with palladium nanoparticles (Pd?MOFs). This strategy for forming symmetric C-C bond between benzene rings has obvious advantages such as high efficiency, easy separation, good recyclability and no addition of toxic halogenated benzene.
- Bao, Yan-Sai,Cui, Xin-Yu,Han, Zheng-Bo,Li, Xin,Tang, Hong,Yang, Ming,Zhang, Yu-Yang,Zhao, Kun,Zhou, Mei-Li
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- The graphite-catalyzed: ipso -functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes
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An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium. A range of carbon materials has been tested as carbocatalysts. To our surprise, graphite was found to be the best catalyst in terms of the turnover frequency. A broad range of valuable substituted aromatic compounds, i.e., phenols, anilines, nitroarenes, and haloarenes, has been prepared via the functionalization of the C-B bond into C-N, C-O, and many other C-X bonds. The vital role of the aromatic π-conjugation system of graphite in this protocol has been established and was observed via numerous analytic techniques. The heterogeneous nature of graphite facilitates the high recyclability of the carbocatalyst. This effective and easy system provides a multipurpose approach for the production of valuable substituted aromatic compounds without using any metals, ligands, bases, or harsh oxidants.
- Badgoti, Ranveer Singh,Dandia, Anshu,Parewa, Vijay,Rathore, Kuldeep S.,Saini, Pratibha,Sharma, Ruchi
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p. 18040 - 18049
(2021/05/29)
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- Chemoselective Cleavage of Si-C(sp3) Bonds in Unactivated Tetraalkylsilanes Using Iodine Tris(trifluoroacetate)
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Organosilanes are synthetically useful reagents and precursors in organic chemistry. However, the typical inertness of unactivated Si-C(sp3) bonds under conventional reaction conditions has hampered the application of simple tetraalkylsilanes in organic synthesis. Herein we report the chemoselective cleavage of Si-C(sp3) bonds of unactivated tetraalkylsilanes using iodine tris(trifluoroacetate). The reaction proceeds smoothly under mild conditions (-50 °C to room temperature) and tolerates various polar functional groups, thus enabling subsequent Tamao-Fleming oxidation to provide the corresponding alcohols. NMR experiments and density functional theory calculations on the reaction indicate that the transfer of alkyl groups from Si to the I(III) center and the formation of the Si-O bond proceed concertedly to afford an alkyl-λ3-iodane and silyl trifluoroacetate. The developed method enables the use of unactivated tetraalkylsilanes as highly stable synthetic precursors.
- Matsuoka, Keitaro,Komami, Narumi,Kojima, Masahiro,Mita, Tsuyoshi,Suzuki, Kimichi,Maeda, Satoshi,Yoshino, Tatsuhiko,Matsunaga, Shigeki
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supporting information
p. 103 - 108
(2021/01/13)
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- PhICl2is activated by chloride ions
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A study on the potential activating role of pyridine in the electrophilic chlorination of anisole by PhICl2has led to the discovery that soluble sources of chloride ions activate PhICl2in the reaction at catalytic loadings, greatly increasing the rate of chlorination. It is further shown that presence of chloride increases the rate of decomposition of PhICl2into PhI and Cl2. The specific mechanism by which chloride induces electrophilic chlorination and decomposition of PhICl2remains an open question.
- Tania,Poynder, Tiffany B.,Kaur, Aishvaryadeep,Barwise, Lachlan,Houston, Sevan D.,Nair, Akshay J.,Clegg, Jack K.,Wilson, David J. D.,Dutton, Jason L.
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supporting information
p. 11986 - 11991
(2021/09/06)
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- Catalytic Highly Regioselective C-H Oxygenation Using Water as the Oxygen Source: Preparation of 17O/18O-Isotope-Labeled Compounds
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We found that the oxygen atom of water is activated to iodosylbenzene derivatives via reversible hydrolysis of PhI(OOCR)2 and can be used to the oxygen source for ruthenium(bpga)-catalyzed site-selective C-H oxygenation. Ru(bpga)/PhI(OOCR)2/H2O system, sterically less bulky methinic and methylenic C-H bonds in various compounds can be converted to desired oxygen functional groups in a site-selective manner. Using this method, oxygen-isotope labeled compounds such as d-[3-17O/18O]-mannose can be prepared in a multigram scale.
- Doiuchi, Daiki,Uchida, Tatsuya
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supporting information
p. 7301 - 7305
(2021/10/01)
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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supporting information
p. 1812 - 1819
(2020/03/17)
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- Arene diazonium saccharin intermediates: A greener and cost-effective alternative method for the preparation of aryl iodide
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In the current protocol, the arene diazonium saccharin derivatives were initially produced from various substituted aromatic amines; subsequently, these intermediates were treated with a greener organic iodide for the preparation of the aryl iodide. We tried to choose low-cost, commercially available, biodegradable, recoverable, ecofriendly, and safe reagents and solvents. The arene diazonium saccharin intermediates could be stored in the liquid phase into a refrigerator for a long time with no significant loss activity. The outstanding merits of the current protocol (a) included the partial recovering of saccharin and tetraethylammonium salt, (b) reduce the use of solvents and the reaction steps due to eliminating separation and purification of intermediates, (c) good yield of the sterically hindered substrates, and (d) avoid the generation of heavy metal or corrosive waste.
- Ghaffari Khaligh, Nader,Rafie Johan, Mohd,Shahnavaz, Zohreh,Zaharani, Lia
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p. 535 - 542
(2020/06/01)
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- Asymmetric Iodonio-[3,3]-Sigmatropic Rearrangement to Access Chiral α-Aryl Carbonyl Compounds
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Here we describe an asymmetric [3,3]-sigmatropic rearrangement of aryl iodanes that enables the enantioselective α-arylation of chiral 2-oxazolines, thereby producing valuable chiral α-aryl carbonyl compounds. The success of this protocol hinges on the selective assembly of aryl iodanes with 2-oxazolines and the smooth deprotonation of the in situ-generated iodonium-imine species. The nearly neutral and mild conditions of the reaction allow it to tolerate a wide variety of functional groups. Moreover, the remaining iodine atom in the products not only provides a versatile platform for further elaboration of such molecules but also supplies the asymmetric hypervalent iodine chemistry with a new class of chiral scaffolds.
- Tian, Junsong,Luo, Fan,Zhang, Qifeng,Liang, Yuchen,Li, Dongyang,Zhan, Yaling,Kong, Lichun,Wang, Zhi-Xiang,Peng, Bo
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p. 6884 - 6890
(2020/05/16)
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- METHOD FOR PRODUCING IODINE-CONTAINING SILICON COMPOUND
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A method for producing a silicon compound containing an iodophenyl group, including substituting iodine for a trialkylsilyl ((R0)3Si) group bonded to a phenyl group by using an iodine-containing electrophilic reagent (I-X) as shown by the following reaction equation: where all of R0's may be identical to or different from each other and each represent an alkyl group having 1 to 6 carbon atoms; R1 represents a single bond or a divalent organic group; R2 represents an organic group having 1 to 10 carbon atoms; R3 represents an organic group having 1 to 10 carbon atoms; R represents an organic group having 1 to 6 carbon atoms; n0 is 1, 2, or 3, n1 is 1, 2, or 3, n2 is 0, 1, or 2, and n3 is 0, 1, or 2, provided that 1≤n1+n3≤3; and X represents a counter substituent of iodine, acting as an electrophilic reactive species.
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Paragraph 0040
(2020/06/07)
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- Generation of Organozinc Reagents by Nickel Diazadiene Complex Catalyzed Zinc Insertion into Aryl Sulfonates
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The generation of arylzinc reagents (ArZnX) by direct insertion of zinc into the C?X bond of ArX electrophiles has typically been restricted to iodides and bromides. The insertions of zinc dust into the C?O bonds of various aryl sulfonates (tosylates, mesylates, triflates, sulfamates), or into the C?X bonds of other moderate electrophiles (X=Cl, SMe) are catalyzed by a simple NiCl2–1,4-diazadiene catalyst system, in which 1,4-diazadiene (DAD) stands for diacetyl diimines, phenanthroline, bipyridine and related ligands. Catalytic zincation in DMF or NMP solution at room temperature now provides arylzinc sulfonates, which undergo typical catalytic cross-coupling or electrophilic substitution reactions.
- Klein, Philippe,Lechner, Vivien Denise,Schimmel, Tanja,Hintermann, Lukas
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supporting information
p. 176 - 180
(2019/12/11)
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- A meta-Selective C?H Alumination of Mono-Substituted Benzene by Using An Alkyl-Substituted Al Anion through Hydride-Eliminating SNAr Reaction
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Reaction of an Al-centered anion with toluene proceeded to form C?H cleaved product with a perfect meta-selectivity and a relatively small kinetic isotope effect (KIE, kH/kD=1.51). DFT calculations suggested a two-step reaction mechanism and electronically controlled meta-selectivity arising from the electron-donating methyl group. The reaction with other mono-substituted arenes was also investigated.
- Kurumada, Satoshi,Nakano, Ryo,Sugita, Kengo,Yamashita, Makoto
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supporting information
p. 20381 - 20384
(2020/09/07)
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- Facile Access to Diverse Libraries of Internal Alkynes via Sequential Iododediazoniation/Decarboxylative Sonogashira Reaction in Imidazolium ILs without Ligand or Additive
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Convenient access to diverse libraries of internal alkynes via decarboxylative Sonogashira reaction of alkynyl-carboxylic acids with iodoarenes, employing imidazolium-ILs as solvent, along with piperidine-appended imidazolium [PAIM][NTf2] as task-specific basic IL is demonstrated, without the need for any ligand or additive. The feasibility to perform these reactions by sequential one-pot iododediazoniation/decarboxylative Sonogashira reaction is also shown, and the scope of the methods is underscored by providing 29 examples. The potential for recycling and reuse of the IL solvent is also examined.
- Prabhala, Pavankumar,Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
p. 2061 - 2064
(2019/03/07)
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- Selective Continuous Flow Iodination Guided by Direct Spectroscopic Observation of Equilibrating Aryl Lithium Regioisomers
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The iodination of 4-fluoro-2-(trifluoromethyl)benzonitrile via C-H lithiation and subsequent treatment with iodine under continuous flow conditions is described. Screening identified both LDA and PhLi as effective bases, giving the desired 3-iodo regioisomer as the major product. Use of LDA results in varying amounts of the undesired 5-iodo isomer, while PhLi results in more reliable formation of the 3-iodo product. An initial flow process was developed using PhLi that produced 4-fluoro-3-iodo-2-(trifluoromethyl)benzonitrile in 63% yield on a gram scale. Process modifications to enable pilot-scale operation resulted in a yield decrease to 50%, persistent formation of a byproduct resulting from PhLi addition to the nitrile, and formation of solids during longer runs. As a result, the use of LDA was investigated under continuous flow conditions. In situ NMR and IR spectroscopy allowed observation of the 5-[Li] species and its conversion to the thermodynamically preferred 3-[Li] species. These mechanistic insights drove development of a second-generation continuous flow process using LDA that achieves 30:1 regioselectivity and an 84% solution yield of the desired product (67% isolated yield after recrystallization). Furthermore, this process increases throughput by 10-fold, providing a path to manufacturing-scale operation.
- Dunn, Anna L.,Leitch, David C.,Journet, Michel,Martin, Michael,Tabet, Elie A.,Curtis, Neil R.,Williams, Glynn,Goss, Charles,Shaw, Tony,O'Hare, Bernie,Wade, Charles,Toczko, Matthew A.,Liu, Peng
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p. 129 - 137
(2018/10/09)
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- Hydro/deutero deamination of arylazo sulfones under metal and (photo)catalyst-free conditions
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Hydrodeaminated and monodeuterated aromatics were obtained via a visible-light driven reaction of arylazo sulfones. Deuteration occurs efficiently in deuterated media such as isopropanol-d8 or in THF-d8/water mixtures and exhibits a high tolerance to the nature and the position of the aromatic substituents.
- Amin, Hawraz I.M.,Raviola, Carlotta,Amin, Ahmed A.,Mannucci, Barbara,Protti, Stefano,Fagnoni, Maurizio
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- Electrochemical Synthesis of Aryl Iodides by Anodic Iododesilylation
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An electrochemical access to iodinated aromatic compounds starting from trimethylsilyl-substituted arenes is presented. By design of experiments, highly efficient and mild conditions were identified for a wide range of substrates. A functional group stability test and the synthesis of an important 3-iodobenzylguanidine radiotracer illustrate the scope of this process.
- M?ckel, Robert,Hille, Jessica,Winterling, Erik,Weidemüller, Stephan,Faber, Tabea Melanie,Hilt, Gerhard
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supporting information
p. 442 - 445
(2018/02/21)
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- An efficient gram scale synthesis of aryl iodides from aryl diazofluoroborates in water under mild conditions
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Transition metal-free synthesis of synthetically valuable aryl iodides from aryl diazofluroborates in water under mild conditions has been described. Majority of synthesized aryl iodides are obtained in quantitative yields (>99%) under present reaction conditions. The structural effects due to the substituents present on aryl diazofluoroborates did not show any satisfactory effect on the yields of the aryl iodides. Hence, the methodology presented here was found to be adventitious for the quantitative production of synthetically valuable aryl iodides.
- Gholap, Somnath S.
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p. 594 - 599
(2018/06/26)
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- A general electrochemical strategy for the Sandmeyer reaction
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Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot fashion. Furthermore, the practicality of this process was demonstrated in the multigram scale synthesis of aryl halides using highly inexpensive graphite as the electrode. A series of detailed mechanism studies have been performed, including radical clock and radical scavenger study, cyclic voltammetry analysis and in situ electron paramagnetic resonance (EPR) analysis.
- Liu, Qianyi,Sun, Beiqi,Liu, Zheng,Kao, Yi,Dong, Bo-Wei,Jiang, Shang-Da,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
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p. 8731 - 8737
(2018/12/10)
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- Direct Pd(II)-Catalyzed Site-Selective C5-Arylation of 2-Pyridone Using Aryl Iodides
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A straightforward Pd(II)-catalyzed general strategy was developed for the C5-selective arylation of the 2-pyridone core with easily available aryl iodides. The transformation was highly regioselective and accomplished with a wide scope and functional group tolerance. Silver nitrate played a crucial role in this direct site-selective arylation. The method was extended to synthesize biologically active molecules.
- Maity, Saurabh,Das, Debapratim,Sarkar, Souradip,Samanta, Rajarshi
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supporting information
p. 5167 - 5171
(2018/09/13)
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- Visible-Light-Induced Decarboxylative Iodination of Aromatic Carboxylic Acids
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A convenient, efficient and practical visible-light-induced decarboxylative iodination of aromatic carboxylic acids has been developed, and the corresponding aryl iodides were obtained in good yields. The method shows some advantages including the use of readily available aromatic carboxylic acids as the starting materials, simple and mild conditions, high efficiency, wide substrate scope and tolerance of various functional groups.
- Jiang, Min,Yang, Haijun,Jin, Yunhe,Ou, Lunyu,Fu, Hua
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supporting information
p. 1572 - 1577
(2018/06/26)
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- Visible-Light-Mediated Remote γ-C(sp3)-H Functionalization of Alkylimidates: Synthesis of 4-Iodo-3,4-dihydropyrrole Derivatives
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An efficient and environmentally friendly synthetic approach toward functionalized dihydropyrrole derivatives is reported. The developed protocol proceeds via chemoselective intramolecular N-C bond formation of alkylimidates through 1,5-hydrogen atom transfer from in situ generated imidate N-radicals. The major advantage of this designed strategy lies in the choice of starting materials, mild reaction conditions, high chemo- and diastereoselectivity, clean source of energy, and good functional group tolerance. Further, 4-iododihydropyrroles could be easily transformed into a variety of useful derivatives.
- Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
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supporting information
p. 4964 - 4969
(2018/08/24)
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- A facile and sustainable protocol to the preparation of aryl iodides using stable arenediazonium bis(trifluoromethylsulfonyl)imide salts via the telescopic process
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The preparation of aryl iodides in a telescopic reaction using tert-butyl nitrite as a diazotization reagent and a mixture of bis(trifluoromethane) sulfonamide and glacial acetic acid as a mild acidic agent in ethanol followed by iododediazoniation with tetraethylammonium iodide in water was investigated. The current method has other advantages such as minimized waste by avoiding solvent for the purification of products in diazotization step, simple experimental procedure, and good yield of the sterically hindered aryl amines, metal and strong acid-free waste and environmentally benign conditions. The noteworthy features of this study are the preparation of stable arenediazonium bis(trifluoromethylsulfonyl)imide salts that can be used with no significant loss activity after 1?week and bis(trifluoromethane)sulfonamide was recovered in high yields from reactions.
- Khaligh, Nader Ghaffari
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- Metathesis-active ligands enable a catalytic functional group metathesis between aroyl chlorides and aryl iodides
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Current methods for functional group interconversion have, for the most part, relied on relatively strong driving forces which often require highly reactive reagents to generate irreversibly a desired product in high yield and selectivity. These approaches generally prevent the use of the same catalytic strategy to perform the reverse reaction. Here we describe a catalytic functional group metathesis approach to interconvert, under CO-free conditions, two synthetically important classes of electrophiles that are often employed in the preparation of pharmaceuticals and agrochemicals—aroyl chlorides (ArCOCl) and aryl iodides (ArI). Our reaction design relies on the implementation of a key reversible ligand C–P bond cleavage event, which enables a non-innocent, metathesis-active phosphine ligand to mediate a rapid aryl group transfer between the two different electrophiles. Beyond enabling a practical and safer approach to the interconversion of ArCOCl and ArI, this type of ligand non-innocence provides a blueprint for the development of a broad range of functional group metathesis reactions employing synthetically relevant aryl electrophiles.
- Lee, Yong Ho,Morandi, Bill
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p. 1016 - 1022
(2018/09/06)
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- Combination of PhI(OAc)2 and 2-Nitropropane as the Source of Methyl Radical in Room-Temperature Metal-Free Oxidative Decarboxylation/Cyclization: Construction of 6-Methyl Phenanthridines and 1-Methyl Isoquinolines
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A room-temperature metal-free method for generating highly unstable methyl radical was realized from the combination of PhI(OAc)2 and 2-nitropropane, which provides an efficient approach to methylated phenanthridines and isoquinolines. The strategy was also extended to the generation of other alkyl radicals and a concise synthesis of Roxadustat.
- Lu, Shi-Chao,Li, Hong-Shuang,Gong, Ya-Ling,Zhang, Shi-Peng,Zhang, Ji-Guo,Xu, Shu
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p. 15415 - 15425
(2019/01/03)
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- N-Iodosuccinimide (NIS) in Direct Aromatic Iodination
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N-Iodosuccinimide (NIS) in pure trifluoroacetic acid (TFA) offers a time-efficient and general method for the iodination of a wide range of mono- and disubstituted benzenes at room temperature, as demonstrated in this paper. The starting materials were generally converted into mono-iodinated products in less than 16 hours at room temperature, without byproducts. A few deactivated substrates needed addition of sulfuric acid to increase the reaction rate. Another exception was methoxybenzenes that preferentially were iodinated by NIS in acetonitrile with only catalytic amounts of TFA.
- Bergstr?m, Maria,Suresh, Ganji,Naidu, Veluru Ramesh,Unelius, C. Rikard
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p. 3234 - 3239
(2017/06/21)
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- Copper-catalysed aromatic-Finkelstein reactions with amine-based ligand systems
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A new efficient and low-cost ligand, diethylenetriamine, has been utilised to promote the iodination of 16 different bromo-substrates via the copper catalysed Finkelstein halogen exchange reaction under mild conditions. In contrast to earlier methods, the use of inert atmosphere conditions was not required to obtain high yields and purity. Studies on the speciation of the catalyst in solution indicate rapid disproportionation of copper(i) in the presence of diethylenetriamine to give copper(0) and a bis-ligated copper(ii) complex which is characterised by X-ray diffraction. This copper(ii) complex was also shown to be catalytically active in the halogen exchange reaction. In contrast, no significant disproportionation was observed using dimethylethylenediamine as the ligand, and the solid-state structures of a copper(i) dimeric complex and a 2D polymeric network of copper(i) iodide tetramers are reported. The catalytic activity of diethylenetriamine and dimethylethylenediamine with both copper(i) and copper(ii) salts are compared, and possible mechanistic implications discussed.
- Jin, Xiaodong,Davies, Robert P.
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p. 2110 - 2117
(2017/07/22)
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- Salicylic Acid-Catalyzed One-Pot Hydrodeamination of Aromatic Amines by tert-Butyl Nitrite in Tetrahydrofuran
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A significant acceleration in the hydrodeamination of in situ formed diazonium salts (from aromatic amines) has been observed in the presence of 10-mol% salicylic acid, using tetrahydrofuran as the hydrogen donor. The reaction proceeds efficiently at 20 °C for a wide range of substituted anilines, even at 10-mmol scale, without any other additive. The same protocol has been adapted to the selective deuterodeamination of some aromatic amines. Control experiments clearly show that aryl radicals are involved in the reaction mechanism. (Figure presented.).
- Felipe-Blanco, Diego,Alonso, Francisco,Gonzalez-Gomez, Jose C.
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supporting information
p. 2857 - 2863
(2017/08/23)
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- A green organic boron reagent carbon boron key cracking hydrogenation of the new method (by machine translation)
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The invention relates to a kind of green, efficient organic boron reagent carbon boron key cracking hydrogenation of the new method. The method uses a cheap and easily obtained inorganic base as catalyst, common organic alcohol as the reaction solvent and a hydrogen source, is placed under the environment of air can be conveniently catalytic organic boric acid or borate generating carbon boron key cracking hydrogenation reaction, the reaction substrate universality is wide, functional group compatibility outstanding. System realizing metallic catalytic various boric acid and boric acid ester in the fracture of the carbon boron key reaction, also overcome the traditional method requires the use of greatly excessive inorganic alkali, organic acid in great harm to the environment or complex metal catalyst to the limitations of the b-hydrogenation, laboratory preparation and industrial production organoboron reagent of the b-hydrogenation reaction provides a completely new strategy. (by machine translation)
- -
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Paragraph 0028; 0029
(2017/10/09)
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- Simple and Efficient Generation of Aryl Radicals from Aryl Triflates: Synthesis of Aryl Boronates and Aryl Iodides at Room Temperature
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Despite the wide use of aryl radicals in organic synthesis, current methods to prepare them from aryl halides, carboxylic acids, boronic acids, and diazonium salts suffer from limitations. Aryl triflates, easily obtained from phenols, are promising aryl radical progenitors but remain elusive in this regard. Inspired by the single electron transfer process for aryl halides to access aryl radicals, we developed a simple and efficient protocol to convert aryl triflates to aryl radicals. Our success lies in exploiting sodium iodide as the soft electron donor assisted by light. This strategy enables the scalable synthesis of two types of important organic molecules, i.e., aryl boronates and aryl iodides, in good to high yields, with broad functional group compatibility in a transition-metal-free manner at room temperature. This protocol is anticipated to find potential applications in other aryl-radical-involved reactions by using aryl triflates as aryl radical precursors.
- Liu, Wenbo,Yang, Xiaobo,Gao, Yang,Li, Chao-Jun
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p. 8621 - 8627
(2017/07/06)
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- Compounds and methods for the reduction of halogenated hydrocarbons
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The present application relates to methods for the reduction of halogenated hydrocarbons using compounds of Formula (I): wherein the reduction of the halogenated compounds is carried out, for example, under ambient conditions without the need for a transition metal containing co-factor. The present application also relates to methods of recovering precious metals using compounds of Formula (I) that are absorbed onto a support material.
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Page/Page column 17
(2017/12/27)
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- Eco-compatible zeolite-catalysed continuous halogenation of aromatics
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A completely eco-compatible halogenation reaction of arenes has been developed allowing high conversions (>95%) of iodobenzene with nearly 100 kg iodobenzene converted per kgcat in one day. Several solid acids, zeolites being the most promising, have been successfully tested in the chlorination reaction of iodobenzene by using trichloroisocyanuric acid (TCCA), a green chlorination agent. H-?BEA zeolites were found to be the most active catalysts for this model halogenation reaction. A strong structure-activity relationship could be established by thorough characterisation (SEM, BET, XRD, FTIR) of various synthetic zeolites. Indeed, nano-sized ?BEA zeolites and more specifically nanosponge-like ?BEA crystals exhibited the highest catalytic performance with a conversion up to 100% and a selectivity toward monochlorinated products up to 98%. Finally, the gained knowledge was applied to set-up an eco-compatible continuous flow halogenation process of different aromatics catalysed by H-?BEA zeolites.
- Losch,Kolb,Astafan,Daou,Pinard,Pale,Louis
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p. 4714 - 4724
(2016/09/04)
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- Easy Access to Difluoromethylene-Containing Arene Analogues through Palladium-Catalysed C–H Olefination
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An efficient palladium-catalysed ortho-C–H olefination of α,α-difluorophenylacetic acid derivatives using 8-aminoquinoline as a bidentate directing group has been developed. A range of olefinated arenes can thus be synthesized in a concise way. This reaction provides an easy and straightforward route to a panel of difluoromethylated arene analogues in moderate to good yields, with a satisfactory tolerance of common functional groups. Transformation of the products into a variety of other difluoromethylene-containing compounds demonstrates the utility of this method.
- Shao, Changdong,Shi, Guangfa,Zhang, Yanghui
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supporting information
p. 5529 - 5538
(2016/11/25)
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- Ligand- and Base-Free Access to Diverse Biaryls by the Reductive Coupling of Diaryliodonium Salts
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A ligand- and base-free, Pd-catalyzed protocol to access a wide range of symmetrical and unsymmetrical biaryls from stable diaryliodonium salts was developed. The reaction involved the use of an effective and recyclable Pd/polyethylene glycol-400 catalyst system to harness the aryl moieties of two diaryliodonium salts; the ensuing biaryls may be utilized to synthesize an array of useful compounds, including 5-aryluracils, carbazoles, chromenones, fluorenones, phenathridines, and boscalid analogues.
- Arun,Reddy, P. O. Venkataramana,Pilania, Meenakshi,Kumar, Dalip
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p. 2096 - 2100
(2016/05/09)
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- Copper-catalyzed conversion of aryl and heteroaryl bromides into the corresponding iodide
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An efficient method for the synthesis of aryl and heteroaryl iodides is described in this study. The reactions of aryl and heteroaryl bromides with potassium iodide proceeded smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding iodides in satisfactory to excellent yields.
- Feng, Xiujuan,Li, Lingyu,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
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p. 129 - 132
(2016/07/06)
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- Copper-mediated aerobic iodination and perfluoroalkylation of boronic acids with (CF3)2CFI at room temperature
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The copper-mediated aerobic reactions between the branched (CF3)2CFI and boronic acids (R-B(OH)2) are described. Different from the linear perfluoroalkyl analogs CF3(CF2)nI (n?=?2, 3, 5, 7), (CF3)2CFI reacting with R-B(OH)2at room temperature under air in the presence of catalytic Cu powder provided exclusively the corresponding iodides (R-I), while the aerobic reactions of arylboronic acids with (CF3)2CFI at room temperature in the presence of Cu(OAc)2gave the perfluoroalkylation products (R-CF(CF3)2) in acceptable to moderate yields. The iodination reaction could be further promoted by hydroquinone, the addition of which improved the oxidation ability of (CF3)2CFI and provided the ipso-iodination products in high yields. The perfluoroalkylation was facilitated by the copper carboxylates since the addition of these salts into the reaction mixtures could successfully give rise to Ar-CF(CF3)2.
- Liu, Xi-Hai,Leng, Jing,Jia, Su-Jiao,Hao, Jian-Hong,Zhang, Fanglin,Qin, Hua-Li,Zhang, Cheng-Pan
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- Bimetallic C-C Bond-Forming Reductive Elimination from Nickel
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Ni-catalyzed cross-coupling reactions have found important applications in organic synthesis. The fundamental characterization of the key steps in cross-coupling reactions, including C-C bond-forming reductive elimination, represents a significant challenge. Bimolecular pathways were invoked in early proposals, but the experimental evidence was limited. We present the preparation of well-defined (pyridine-pyrrolyl)Ni monomethyl and monophenyl complexes that allow the direct observation of bimolecular reductive elimination to generate ethane and biphenyl, respectively. The sp3-sp3 and sp2-sp2 couplings proceed via two distinct pathways. Oxidants promote the fast formation of Ni(III) from (pyridine-pyrrolyl)Ni-methyl, which dimerizes to afford a bimetallic Ni(III) intermediate. Our data are most consistent with the subsequent methyl coupling from the bimetallic Ni(III) to generate ethane as the rate-determining step. In contrast, the formation of biphenyl is facilitated by the coordination of a bidentate donor ligand.
- Xu, Hongwei,Diccianni, Justin B.,Katigbak, Joseph,Hu, Chunhua,Zhang, Yingkai,Diao, Tianning
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p. 4779 - 4786
(2016/05/09)
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- PIDA-I2 mediated direct vicinal difunctionalization of olefins: Iodoazidation, iodoetherification and iodoacyloxylation
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Iodinium cation (I+ or IOAc) was produced from the combination of phenyliodine diacetate (PIDA) and iodine. I+ facilitated the direct vicinal difunctionalization of olefins to α-azido, α-trideuteriomethoxy, α-2,2,2-trifluoroethoxy and α-acyloxy alkyl iodides via cation-π interaction at room temperature and under transition-metal free conditions.
- Achar, Tapas Kumar,Maiti, Saikat,Mal, Prasenjit
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p. 4654 - 4663
(2016/06/09)
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- Single-Electron-Transfer-Induced Coupling of Alkylzinc Reagents with Aryl Iodides
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Alkylzinc reagents prepared from an alkyllithium and zinc iodide were found to undergo coupling with aryl and alkenyl iodides in the presence of LiI in a mixed solvent consisting of THF and diglyme (1:1). Alkyllithiums, prepared by halogen–lithium exchange between an alkyl iodide and tert-butyllithium, are also converted to alkylarenes through alkylzinc reagents.
- Okura, Keisho,Shirakawa, Eiji
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supporting information
p. 3043 - 3046
(2016/07/14)
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- Application of "click" chemistry in solid phase synthesis of alkyl halides
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A convenient and highly selective microwave assisted procedure for the conversion of allylic, benzylic and aliphatic alcohols to their corresponding halides using polymer-bound triphenylphosphine and iodine is presented. In case of symmetrical diols, mono-iodination product is obtained in very high yield. Additionally, highly regioselective behavior is observed in our procedure. Simplicity in operation, no column chromatography required for the purification of the products, recyclability of the reagents used, short reaction times and good to excellent yields are the advantages of our protocol. Most functional groups remain unaffected under our reaction condition.
- Das, Diparjun,Chanda, Tridib,Rokhum, Lalthazuala
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p. 775 - 783
(2016/01/20)
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- Compartmentalization of incompatible reagents within Pickering emulsion droplets for one-pot cascade reactions
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It is a dream that future synthetic chemistry can mimic living systems to process multistep cascade reactions in a one-pot fashion. One of the key challenges is the mutual destruction of incompatible or opposing reagents, for example, acid and base, oxidants and reductants. A conceptually novel strategy is developed here to address this challenge. This strategy is based on a layered Pickering emulsion system, which is obtained through lamination of Pickering emulsions. In this working Pickering emulsion, the dispersed phase can separately compartmentalize the incompatible reagents to avoid their mutual destruction, while the continuous phase allows other reagent molecules to diffuse freely to access the compartmentalized reagents for chemical reactions. The compartmentalization effects and molecular transport ability of the Pickering emulsion were investigated. The deacetalization-reduction, deacetalization-Knoevenagel, deacetalization-Henry and diazotization-iodization cascade reactions demonstrate well the versatility and flexibility of our strategy in processing the one-pot cascade reactions involving mutually destructive reagents. (Figure Presented).
- Yang, Hengquan,Fu, Luman,Wei, Lijuan,Liang, Jifen,Binks, Bernard P.
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supporting information
p. 1362 - 1371
(2015/02/19)
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- C-H arylation of triphenylene, naphthalene and related arenes using Pd/C
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A highly selective arylation of a number of polyaromatic hydrocarbons (PAHs) with aryliodonium salts and Pd/C as the only reagent is reported. The first C-H functionalization of triphenylene is explored, and proceeds at the most sterically hindered position. This non-chelate assisted C-H functionalization extends the reactivity profile of Pd/C and provides controlled access to π-extended PAHs, an important aspect of work towards the preparation of nanographenes. Mechanistic studies suggest in situ formation of catalytically active insoluble nanoparticles, and that the reaction likely proceeds via a Pd(0)/Pd(II) type reaction manifold.
- Collins, Karl D.,Honeker, Roman,Vásquez-Céspedes, Suhelen,Tang, Dan-Tam D.,Glorius, Frank
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p. 1816 - 1824
(2015/05/27)
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- Photo-induced Metal-Catalyst-Free Aromatic Finkelstein Reaction
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The facile iodination of aromatic compounds under mild conditions is a great challenge for both organic and medicinal chemistry. Particularly, the synthesis of functionalized aryl iodides by light has long been considered impossible due to their photo-lability, which actually makes aryl iodides popular starting materials in many photo-substitution reactions. Herein, a photo-induced halogen exchange in aryl or vinyl halides has been discovered for the first time. A broad scope of aryl iodides can be prepared in high yields at room temperature under exceptionally mild conditions without any metal or photo-redox catalysts. The presence of a catalytic amount of elemental iodine could promote the reaction significantly.
- Li, Lu,Liu, Wenbo,Zeng, Huiying,Mu, Xiaoyue,Cosa, Gonzalo,Mi, Zetian,Li, Chao-Jun
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supporting information
p. 8328 - 8331
(2015/07/15)
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