Pd(ii) catalyzed ortho C–H iodination of phenylcarbamates at room temperature using cyclic hypervalent iodine reagents

2015 ◽  
Vol 51 (49) ◽  
pp. 10014-10017 ◽  
Author(s):  
Xiuyun Sun ◽  
Xia Yao ◽  
Chao Zhang ◽  
Yu Rao
Keyword(s):  
Room Temperature ◽  
Functional Group ◽  
Hypervalent Iodine ◽  
Weak Coordination ◽  
Unique Mechanism

The first example to access ortho iodinated phenols using cyclic hypervalent iodine(iii) reagents through palladium(ii) catalyzed C–H activation has been developed via weak coordination. The reaction showed excellent regioselectivity, reactivity and good functional group tolerance. A unique mechanism was proposed.

Synthesis of O-Aroyl-N,N-dimethylhydroxylamines through Hypervalent Iodine-Mediated Amination of Carboxylic Acids with N,N-Dimethylformamide

Synthesis ◽  
2017 ◽  
Vol 49 (18) ◽  
pp. 4303-4308 ◽  
Author(s):  
Dong Li ◽  
Chuancheng Zhang ◽  
Qiang Yue ◽  
Zhen Xiao ◽  
Xianglan Wang ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Room Temperature ◽  
Functional Group ◽  
Hypervalent Iodine ◽  
Electrophilic Amination ◽  
Mild Conditions

An efficient protocol for the synthesis of O-aroyl-N,N-dimethylhydroxylamines, which are important electrophilic amination reagents, is described. The reaction between carboxylic acids and N,N-dimethylformamide is mediated by hypervalent iodine and occurs under mild conditions at room temperature to give the desired products in good yields. The process shows good functional group compatibility and air and moisture tolerance.

Conformation and electronic structure of aromatic chloroformates

1987 ◽  
Vol 52 (4) ◽  
pp. 970-979 ◽  
Author(s):  
Otto Exner ◽  
Pavel Fiedler
Keyword(s):  
Electronic Structure ◽  
Oxygen Atom ◽  
Strong Interaction ◽  
Electron Distribution ◽  
Room Temperature ◽  
Functional Group ◽  
Dipole Moments ◽  
Carbonyl Oxygen ◽  
Nonpolar Solvents ◽  
Single Method

Aromatic chloroformates Ib-Ie were shown to exist in the ap conformation, in agreement with aliphatic chloroformates, i.e. the alkyl group is situated cis to the carbonyl oxygen atom as it is the case in all esters. While 4-nitrophenyl chloroformate (Ie) is in this conformation in crystal, in solution at most several tenths of percent of the sp conformation may be populated at room temperature and in nonpolar solvents only. A new analysis of dipole moments explained the previous puzzling results and demonstrated the impossibility to determine the conformation by this single method, in consequence of the strong interaction of adjoining bonds. If, however, the ap conformation is once proven, the dipole moments reveal some features of the electron distribution on the functional group, characterized by the enhanced polarity of the C-Cl bond and reduced polarity of the C=O bond. This is in agreement with the observed bond lengths and angles.

Rh(III)-Catalyzed Olefination and Alkylation of Arenes with Maleimides: A Tunable Strategy for C(sp2)–H Functionalization

Synthesis ◽  
2021 ◽  
Author(s):  
Hongji Li ◽  
Wenjie Zhang ◽  
Xueyan Liu ◽  
Zhenfeng Tian
Keyword(s):  
Room Temperature ◽  
Functional Group ◽  
Reaction Conditions ◽  
Bond Functionalization ◽  
Alkylation Process ◽  
Coupling Partner

AbstractWe herein report a new nitrogen-directed Rh(III)-catalyzed C(sp2)–H bond functionalization of N-nitrosoanilines and azoxybenzenes with maleimides as a coupling partner, in which the olefination/alkylation process can be finely controlled at room temperature by variation of the reaction conditions. This method shows excellent functional group tolerance, and presents a mild access to the resulting olefination/alkylation products in moderate to good yields.

scholarly journals Practical Synthesis of 2-Iodosobenzoic Acid (IBA) without Contamination by Hazardous 2-Iodoxybenzoic Acid (IBX) under Mild Conditions

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1897
Author(s):  
Hideyasu China ◽  
Nami Kageyama ◽  
Hotaka Yatabe ◽  
Naoko Takenaga ◽  
Toshifumi Dohi
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Practical Method ◽  
Hypervalent Iodine ◽  
Mild Conditions ◽  
Sequential Procedures ◽  
Iodine Compounds ◽  
Practical Synthesis ◽  
Iodosobenzoic Acid ◽  
Lower Temperature

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.

Diiiodine/Potassium Persulfate Mediated Synthesis of 1,2,3-Thiadiazoles from N-Tosylhydrazones and a Thiocyanate Salt as a Sulfur Source under Transition-Metal-Free Conditions

Synlett ◽  
2021 ◽  
Author(s):  
Yadong Sun ◽  
Ablimit Abdukader ◽  
Yuhan Lu ◽  
Chenjiang Liu
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Room Temperature ◽  
Functional Group ◽  
Ammonium Thiocyanate ◽  
Potassium Persulfate ◽  
Sulfur Source ◽  
Coupling Reactions ◽  
Wide Scope ◽  
Metal Free

AbstractA highly efficient method for the synthesis of 1,2,3-thiadiazoles has been developed by utilizing readily available tosylhydrazones and ammonium thiocyanate with ecofriendly EtOH as the solvent at room temperature. The reaction shows a wide scope of substrates and good functional-group tolerance. This protocol can be scaled up to a gram level and can be applied to coupling reactions with 4-(4-bromophenyl)-1,2,3-thiadiazole as the substrate.

Functional Group Manipulations

2008 ◽  
Author(s):  
Jie Jack Li ◽  
Chris Limberakis ◽  
Derek A. Pflum
Keyword(s):  
Column Chromatography ◽  
Room Temperature ◽  
Functional Group ◽  
Lithium Bromide ◽  
Methyl Methanesulfonate ◽  
Organic Layer ◽  
Reduced Pressure ◽  
Organic Extracts ◽  
Aqueous Layer ◽  
G 34

CBr4–Ph3P is very straightforward and widely used. Workup and purification can be messy at times because of the by-product, Ph3PO. To a mixture of the alcohol (0.800 g, 3.36 mmol) and carbon tetrabromide (1.337 g, 4.03 mmol) in CH2Cl2 at 0 ºC was added a solution of PPh3 (1.319 g, 5.03 mmol) in CH2Cl2 (3 mL). The reaction mixture was stirred at room temperature for 1 h, concentrated under reduced pressure, and purified by column chromatography to afford the bromide (0.941 g, 93% yield). Reference: Hu, T.-S.; Yu, Q.; Wu, Y.-L.; Wu, Y. J. Org. Chem. 2001, 66, 853–861. A two-step sequence consisting of mesylate formation followed by treatment with LiBr can also be used. This procedure involves two steps, but workup and purification are very straightforward. The bromide can be carried out to the next step without further purification in many cases. To a solution of 5-hydroxymethyl-1-methylcyclopentene (3.8 g, 34 mmol) in CH2 Cl2 (50 mL) at 0 ºC was added triethylamine (5.2 mL, 37 mmol) followed by methanesulfonyl chloride (2.9 mL, 37 mmol). The mixture was stirred at 0 ºC for 5 h and then water was added. The organic layer was separated and the aqueous layer was extracted with ether. The combined organic extracts were dried over MgSO4 and the solvent was removed under reduced pressure to give 6.4 g (98%) of (2-methylcyclopent-2- enyl)methyl methanesulfonate, which was used in the next step without further purification. A solution containing the mesylate (6.4 g, 34 mmol) in acetone (70 mL) was treated with lithium bromide (8.89 g, 102 mmol). The mixture was heated at reflux for 6 h, cooled to room temperature, diluted with water, extracted with ether, and the combined ethereal extracts were dried over MgSO4. Removal of the solvent under reduced pressure gave 4.6 g (78%) of 5-bromomethyl-1-methylcyclopentene, which was used in the next step without further purification.

Hypervalent Iodine(III)-Catalyzed Epoxidation of β-Cyanostyrenes

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4473-4486 ◽  
Author(s):  
Saeesh R. Mangaonkar ◽  
Fateh V. Singh
Keyword(s):  
Reaction Time ◽  
Room Temperature ◽  
Hypervalent Iodine ◽  
Short Reaction Time ◽  
Convenient Approach

A convenient approach for the synthesis of β-cyanoepoxides is illustrated by iodine(III)-catalyzed epoxidation of electron-deficient β-cyanostyrenes, wherein the active catalytic iodine(III) species was generated in situ. The epoxidation of β-cyanostyrenes was performed using 10 mol% PhI as precatalyst in the presence of 2.0 equivalents Oxone as an oxidant and 2.4 equivalents of TFA as an additive at room temperature under ultrasonic radiations. The β-cyanoepoxides were isolated in good to excellent yields in a short reaction time.

scholarly journals Effect of Functionalized Carbon Nanotubes in the Detection of Benzene at Room Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Nurjahirah Janudin ◽  
Norli Abdullah ◽  
Wan Md Zin Wan Yunus ◽  
Faizah Md Yasin ◽  
Mohd Hanif Yaacob ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Acid Treatment ◽  
Room Temperature ◽  
Functional Group ◽  
Group Performance ◽  
Active Area ◽  
Functionalized Carbon Nanotubes ◽  
Sensing Material

In this paper, carbon nanotubes (CNTs) were functionalized by acid treatment and further functionalized with dodecylamine and were designated as CNT-carboxylic and CNT-amide, respectively. Then, functionalized CNTs produced were characterized with various methods to verify the attachment of a functional group. Performance of the functionalized CNTs in the detection of benzene gas was monitored at room temperature. The sample was dropped cast on the interdigitated transducer (IDT), and the changes in resistivity were recorded by a digital multimeter in a customized chamber under controlled humidity (∼55%) environment. Based on the findings, it showed that the functionalized CNTs provide an extra active area for interaction between the gas analyte and CNTs, thus increasing their response and improving the sensitivity of the sensing material.

Finely tuning MOFs towards high performance in C2H2 storage: synthesis and properties of a new MOF-505 analogue with an inserted amide functional group

2016 ◽  
Vol 52 (45) ◽  
pp. 7241-7244 ◽  
Author(s):  
Mingxing Zhang ◽  
Bin Li ◽  
Yunzhi Li ◽  
Qian Wang ◽  
Wenwei Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Functional Group ◽  
Powerful Absorption

NJU-Bai 17, a new analogue of MOF-505 with the new and powerful absorption site of the amide and almost record high C2H2 uptake at room temperature was designed.

Dehydroxymethyl Bromination of Alkoxybenzyl Alcohols by Using a Hypervalent Iodine Reagent and Lithium Bromide

Synlett ◽  
2018 ◽  
Vol 29 (17) ◽  
pp. 2275-2278
Author(s):  
Tomohiro Maegawa ◽  
Ayako Shibata ◽  
Sara Kitamoto ◽  
Kazuma Fujimura ◽  
Yuuka Hirose ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lithium Bromide ◽  
Hypervalent Iodine ◽  
Molar Ratios

We describe the dehydroxymethylbromination of alkoxybenzyl alcohol by using a hypervalent iodine reagent and lithium bromide in F3CCH2OH at room temperature. Selective monobromination or dibromination was possible by adjusting the molar ratios of hypervalent iodine reagent and lithium bromide.

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