- Synthesis of Stannylated Aryl Imines and Amines via Aryne Insertion Reactions into Sn?N Bonds
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The reaction of in situ generated arynes with stannylated imines to provide ortho-stannyl-aniline derivatives is reported. The readily prepared trimethylstannyl benzophenone imine is introduced as an efficient reagent to realize the aryne σ-insertion reaction. The imine functionality is an established N-protecting group and insertions proceed with good yields and good to excellent regioselectivities. The product anilines are valuable starting materials for follow-up chemistry thanks to the rich chemistry offered by the trimethylstannyl moiety.
- Kran, Eva,Mück-Lichtenfeld, Christian,Daniliuc, Constantin G.,Studer, Armido
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supporting information
p. 9281 - 9285
(2021/05/31)
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- A dinuclear rhenium complex in the electrochemically driven homogeneous and heterogeneous H+/CO2-reduction
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A dinculear Re(CO)3 complex with a proton responsive phenol unit and a pyrene anchor in the ligand backbone was investigated in the electrochemical CO2/H+ conversion in solution and adsorbed on multi walled carbon nanotubes (MWCNT) on an GC electrode surface. The pyrene group unit is introduced at the end of the ligand synthesis via a coupling reaction, which allows for a versatile ligand modification in order to tune the electronic properties or to introduce various anchor groups for heterogenisation at a late stage. The redox chemistry of the pyrene-α-diimine-Re(CO)3 complex, 1, was investigated in N,N-dimethylformamide (dmf), including IR-spectroelectrochemical (IR-SEC) characterisation of the short lived, reduced species. Subsequently, the electrochemical H+/CO2-reduction catalysis in dmf/water was investigated. The complex catalyses syngas formation yielding CO and H2 with similar rates, namely in Faraday yields of 45% and 35%, respectively. Since the similar complex without the pyrene anchor in the backbone, I, prefers CO2 over H+ reduction, the formation of syngas was rationalised by the small differences in the redox properties and pKa values of the phenol-pyrene unit in regard to phenol unit as in I. Subsequently, the complex was adsorbed on multi walled carbon nanotubes (MWCNT) on a GC electrode surface. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) confirmed coating of the electrode. The immobilised complex was utilised in the electrochemical CO2/H+ reduction in dmf/water, however, the complex quickly desorbed under reductive conditions, likely due to the good solubility of the reduced species. Water as a solvent prevents desorption as confirmed by XPS, however, then a preference for H2 formation over syngas formation was observed under electrocatalytic conditions. Thus, these experiments show, that the results obtained in aqueous organic solution are not easily transferable to the heterogeneous systems operating in water due to changes in the reaction rates for competing pathways.
- Ebrahimi, Fatemeh,Jooss, Christian,Meyer, Franc,Paul, Lucas A.,Rajabi, Sheida,Siewert, Inke
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supporting information
p. 8367 - 8374
(2020/07/07)
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- Two-stage metal ion sensing by through-space and through-bond charge transfer
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A highly selective colorimetric and ratiometric "two-stage"/"off-on"type fluorescent probe with an ability to exclude other heavy and transition metal ions has been designed and synthesized. Low concentrations of Fe3+ cause through-space charge transfer which leads to fluorescence quenching exceeds 96%, and a further increase of Fe3+ concentration results in the formation of a complex with the maximum emission peak of 1,3-bis((E)-2-(pyridin-4-yl)vinyl)-2-methoxy benzene (BPVMB) being shifted largely by 100 nm (from 416 to 516 nm), which was examined by fluorescence, absorption detection and femtosecond transient absorption measurements on the basis of intramolecular charge transfer (ICT).
- Chen, Rui,Li, Ruxue,Wang, Hsing-Lin,Wang, Yu,Yin, Guoxin,Yuan, Yuping
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p. 14028 - 14036
(2020/11/02)
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- Aryne Trifunctionalization Enabled by 3-Silylaryne as a 1,2-Benzdiyne Equivalent
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An unprecedented aryne 1,2,3-trifunctionalization protocol from 2,6-bis(silyl)aryl triflates was developed under transition-metal-free conditions. The reaction of generated 3-silylaryne with both pyridine N-oxide and N-hydroxylamide afforded o-silyl triflate/tosylate in a one-pot transformation, allowing the formation of 2,3-aryne precursors with various vicinal pyridinyl/amido substituents. These pyridinyl-substituted 2,3-aryne intermediates exhibit a broad scope of reactivity with diverse arynophiles in good yields and high selectivity.
- Lv, Chunjie,Wan, Caiwen,Liu, Song,Lan, Yu,Li, Yang
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supporting information
p. 1919 - 1923
(2018/04/16)
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- Synthesis of Silylbiaryl Triflates by Chemoselective Suzuki Reaction
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A modular approach for the synthesis of functionalized silylbiaryl triflates has been developed. Iodinated silylaryl triflates were prepared via a gram-scale diiodination reaction, followed by a one-flask transformation, in 42-52% overall yield. The iodin
- Moreira, Bárbara V.,Muraca, Ana Carolina A.,Raminelli, Cristiano
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supporting information
p. 1093 - 1102
(2017/02/24)
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- Regiocomplementary cycloaddition reactions of boryl- and silylbenzynes with 1,3-dipoles: Selective synthesis of benzo-fused azole derivatives
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Benzo-fused nitrogen-containing heterocycles are abundant in biologically active compounds. One of the most important methods for preparing such heterocycles is the (3 + 2) cycloaddition reaction of benzynes with 1,3-dipolar compounds. However, the reacti
- Ikawa, Takashi,Takagi, Akira,Goto, Masahiko,Aoyama, Yuya,Ishikawa, Yoshinobu,Itoh, Yuji,Fujii, Satoshi,Tokiwa, Hiroaki,Akai, Shuji
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p. 2965 - 2983
(2013/06/26)
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- 1,3-Phenylene bis(ketoacid) derivatives as inhibitors of Escherichia coli dihydrodipicolinate synthase
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Dihydrodipicolinate synthase is a key enzyme in the lysine biosynthesis pathway that catalyzes the condensation of pyruvate and aspartate semi-aldehyde. A series of phenolic ketoacid derivatives that mimic the proposed enzymatic intermediate were designed
- Boughton, Berin A.,Hor, Lilian,Gerrard, Juliet A.,Hutton, Craig A.
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supporting information; experimental part
p. 2419 - 2426
(2012/05/20)
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- Gas-Chromatographic identifi cation of products formed in iodination of methyl phenols by retention indices
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Iodination reaction followed by conversion of iodine-substituted methylphenols to the corresponding trifl uoroacetates was suggested for improving the sensitivity of the gas-chromatographic determination of phenol and its methyl-substituted derivatives (al isomers of mono- and diethylphenols, 2,3,5-, 2,3,6-, and 3,4,5-trimethylphenols) in aqueous media. Acylation products of iodo methylphenols (104 compounds) were identifi ed by linear-logarithmic retention indices on a standard nonpolar polydimethylsiloxane stationary phase, and the pattern of their variation with the number and nature of substituents were characterized. A procedure for identifi cation of methyl-substituted phenols in water in their gas-chromatographic determination with an electron-capture detector was developed. Pleiades Publishing, Ltd., 2012.
- Gruzdev,Kuzivanov,Zenkevich,Kondratenok
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p. 1355 - 1365
(2013/01/15)
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- A Green protocol for the bromination and iodination of the aromatic compounds using H5IO6/NaBr and H5IO 6/NaI in the water
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Bromination and iodination of the aromatic compounds have efficiently been carried out at room temperature and 70 °C, respectively, in short reaction times using orthoperiodic acid/sodium bromide (1:2) and orthoperiodic acid/sodium iodide (1:2) in water to prepare the corresponding halo compounds with excellent yields.
- Yousefi-Seyf, Jaber,Tajeian, Kazem,Kolvari, Eskandar,Koukabi, Nadiya,Khazaei, Ardeshir,Zolfigol, Mohammad Ali
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p. 2619 - 2622
(2012/10/29)
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- Direct green iodination of phenol over solid acids
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Examination of several solid acid catalysts of different nature (acid resins, zeolites, mixed oxides, Nb-oxide, and Nb-phosphate) was performed for the direct iodination reaction of phenol by using molecular iodine. The experiments were carried out in mil
- Carniti, Paolo,Colonna, Stefano,Gervasini, Antonella
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scheme or table
p. 55 - 62
(2010/09/05)
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- Preparation and regioselective Diels-Alder reactions of borylbenzynes: Synthesis of functionalized arylboronates
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(Figure Presented) B+ [4+2]: 3-Borylbenzynes undergo Diels-Alder reactions with substituted furans and pyrroles to give highly functionalized arylboronic acid derivatives with either good or exclusive regioselectivities (see picture). The effect of the boryl group on the regioselectivity arises from electronic rather than steric effects.
- Ikawa, Takashi,Takagi, Akira,Kurita, Yurio,Saito, Kozumo,Azechi, Kenji,Egi, Masahiro,Kakiguchi, Keisuke,Kita, Yasuyuki,Akai, Shuji
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supporting information; experimental part
p. 5563 - 5566
(2010/09/05)
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- Efficient and selective iodination of phenols promoted by iodine and hydrogen peroxide in water
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A simple and selective reaction for the preparation of iodinated phenols was developed and phenol derivatives containing electron withdrawing groups were iodinated in very good yields under relatively mild conditions.
- Gallo, Rafael D.C.,Gebara, Karimi S.,Muzzi, Rozanna M.,Raminelli, Cristiano
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experimental part
p. 770 - 774
(2010/08/13)
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- Synthesis of halogenated phenols by directed ortho-lithiation and ipso-iododesilylation reactions of O-aryl N-isopropylcarbamates
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The regioselective synthesis of halogenated phenols via directed ortho-lithiation reactions of in situ N-silylated O-aryl N-isopropylcarbamates is reported. This protocol is complemented by ipso-iododesilylation reactions of C-silylated carbamates and iodine-magnesium exchange reactions, which are facilitated by the adjacent carbamoyl group. These methods provide an entry into a series of o-fluoro-, o-iodo-, and o,o′-diiodophenols in high yields which are otherwise difficult to obtain. Georg Thieme Verlag Stuttgart.
- Kauch, Matthias,Hoppe, Dieter
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p. 1578 - 1589
(2007/10/03)
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- Reductive dehalogenation of halophenols in sulfite-bisulfate medium
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The KHSO4-Na2SO3 system is found to be simple and inexpensive for reductive elimination of halogens (Br, I) from the corresponding halophenols under reflux conditions in dry methanol. Under similar conditions the reaction is sluggish with chlorophenols.
- Adimurthy, Subbarayappa,Ramachandraiah, Gadde
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p. 5251 - 5252
(2007/10/03)
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- A novel application of Hβ-zeolite in catalytic dehalogenation of halophenols
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A new application of Hβ-zeolite for debromination of bromophenols and deiodination of iodophenols is presented in this note. The heterogeneous catalyst can be recovered and recycled effectively for subsequent reactions. The catalyst was found ineffective for similar action on chlorophenols.
- Adimurthy, Subbarayappa,Ramachandraiah, Gadde,Bedekar, Ashutosh V.
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p. 6391 - 6392
(2007/10/03)
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