- Comparative theoretical and experimental analysis of hydrocarbon σ-radical cations
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The structures of σ-radical cations formed by ionization of adamantane, twistane, noradamantane, cubane, 2,4-dehydroadamantane, and protoadamantane were optimized at the B3LYP, B3LYP-D, M06-2X, B3PW91, and MP2 levels of theory using 6-31G(d), 6-311+G(d,p), 6-311+G(3df,2p), cc-PVDZ, and cc-PVTZ basis sets. On the whole, single-configuration approximations consistently describe the structure and transformations of the examined σ-radical cations. The best correlations (r = 0.97-0.98) between the calculated adiabatic ionization potentials and experimental oxidation (anodic) potentials of hydrocarbons were obtained in terms of B3PW91 approximation. Pleiades Publishing, Ltd., 2011.
- Novikovskii,Gunchenko,Prikhodchenko,Serguchev,Schreiner,Fokin
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Read Online
- 1-Acetamidoadamantane
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In the title compound, C12H19NO, the bond lengths and angles are closely similar to those of two cagesubstituted 1-acetamidoadamantanes. The molecules are linked into polymeric chains through a weak N-H...O hydrogen bond [H...O 2.04 (2), N...O 2.928 (2) A and N-H...O 168 (1)°].
- Proehl, Hans-Heinrich,Blaschette, Armand,Jones, Peter G.
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Read Online
- Decarboxylative Ritter-Type Amination by Cooperative Iodine (I/III)─Boron Lewis Acid Catalysis
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Recent years have witnessed important progress in synthetic strategies exploiting the reactivity of carbocations via photochemical or electrochemical methods. Yet, most of the developed methods are limited in their scope to certain stabilized positions in molecules. Herein, we report a metal-free system based on the iodine (I/III) catalytic manifold, which gives access to carbenium ion intermediates also on electronically disfavored benzylic positions. The unusually high reactivity of the system stems from a complexation of iodine (III) intermediates with BF3. The synthetic utility of our decarboxylative Ritter-type amination protocol has been demonstrated by the functionalization of benzylic as well as aliphatic carboxylic acids, including late-stage modification of different pharmaceutical molecules. Notably, the amination of ketoprofen was performed on a gram scale. Detailed mechanistic investigations by kinetic analysis and control experiments suggest two mechanistic pathways.
- Narobe, Rok,Murugesan, Kathiravan,Schmid, Simon,K?nig, Burkhard
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p. 809 - 817
(2022/01/15)
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- Preparation method of amantadine
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The invention discloses a preparation method of amantadine, which belongs to the technical field of organic chemical synthesis, and is characterized by comprising the following steps: taking a compound adamantane as an initial raw material, generating an intermediate 1-acetamido adamantane in the presence of acetonitrile, a polyion liquid PIL catalyst and sulfuric acid, and then hydrolyzing the intermediate into amantadine in a system of alcohol and alkali. The preparation method is environment-friendly, post-treatment is convenient, the use amount of sulfuric acid and acetonitrile is greatly reduced through the catalyst polyion liquid, and post-treatment is simple. The ionic liquid catalyst can be recycled, so that the cost is greatly saved, and the method is suitable for large-scale industrial production.
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Paragraph 0112-0123
(2021/06/13)
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- Method for preparing 3-acetamido-1-adamantanol
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The invention discloses a method for preparing 3-acetamido-1-adamantanol, and belongs to the technical field of chemical synthesis. The method comprises the following steps: using adamantane as a starting raw material, adding acetonitrile into fuming sulphuric acid to carry out amidation reaction, and carrying out HNO3 nitration reaction, KOH/H2O alkaline hydrolysis reaction and separation and purification to obtain the 3-acetamido-1-adamantanol. According to the method, the 3-acetamido-1-adamantanol is prepared by adopting a sulfuric acid system continuous utilization method so that the generation of waste acid is reduced, and the method is green, environment-friendly, low in raw material price, rapid in reaction, high in yield, high in purity, simple in process and suitable for industrial production.
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Paragraph 0026; 0030; 0034
(2021/01/29)
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- Method for continuously preparing N-acetyl amantadine
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The invention relates to the technical field of synthesis of N-acetyl amantadine, in particular to a method for continuously preparing N-acetyl amantadine. The method for continuously preparing N-acetyl amantadine comprises the following steps: carrying out continuous reaction in a micro-channel reactor by using adamantane, acetonitrile and acid as raw materials and halogenated alkane as a solvent, wherein the injection speed of adamantane, acetonitrile and halogenated alkane is recorded as V1, the injection speed of the acid is recorded as V2, and (V1+V2)* residence time=liquid holdup is satisfied.
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Paragraph 0026-0049
(2021/04/21)
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- Synthetic method of amantadine hydrochloride (by machine translation)
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Compared, the prior art . the synthesis method: the amantadine hydrochloride has an important clinical value and market value Ritter, and the synthesis process, of the hydrochloric acid adamantanamine, effectively improves the industrial application potential, of the hydrochloric acid adamantane hydrochloride synthesis process as, by adopting a special process and a component, on the one hand for preparation of the medicine, for treating and preventing viral infection, through hydrolysis and purification on the other hand, and effectively solves the problem, of environmental pollution in the synthesis process of the hydrochloric acid adamantanamine by adopting a special process and a component technology; through hydrolysis and purification on an aspect, through hydrolysis and, purification of components . The method mainly, comprises, steps of preparation of an amantadine hydrochloride synthesis process by using a special process and a method. (by machine translation)
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Paragraph 0115-0119; 0145-0149; 0157-0161; 0169-0184
(2020/05/29)
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- Adamantylation of N-aryl and N-arylalkyl acetamides in trifluoroacetic acid
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Alkylation of N-aryl and N-arylalkyl acetamides with hydroxy adamantane derivatives in trifluoroacetic acid was studied. The differentiating effect of trifluoroacetic acid on the regio-selectivity of adamantylation of o-alkyl-substituted acetanilides was established, leading to energetically more stable products of para-substitution with respect to the alkyl group (the content of para-alkyl isomers is 93–94percent). This enabled the synthesis of adamantylaminoarenes in 83–99percent yields and with 95–99percent purity.
- Kireeva, A. V.,Nakhod, M. A.,Novakov, I. A.,Orlinson, B. S.,Pichugin, A. M.,Porkhun, V. I.,Potaenkova, E. A.,Savelyev, E. N.,Vostrikova, O. V.,Zavyalov, D. V.
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p. 1096 - 1101
(2020/07/25)
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
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An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
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supporting information
p. 5303 - 5308
(2020/04/17)
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- Synthetic method of amantadine hydrochloride
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The invention discloses a synthetic method of amantadine hydrochloride. The synthetic method comprises the following steps: preparation of 1-acetamido adamantane, preparation of amantadine and preparation of amantadine hydrochloride, wherein the preparation of the 1-acetamido adamantine comprises the steps of dropwise adding acetonitrile into 20 percent of fuming sulfuric acid, adding a nickel-rhodium bimetallic catalyst and adamantane, rising the temperature, slowly and dropwise adding ice salt water for diluting after completing reaction, extracting, washing, drying, and evaporating and removing a solvent, thus obtaining the 1-acetamido adamantine. The synthetic method disclosed by the invention has the beneficial effects that the alumina supported nickel-rhodium bimetallic catalyst is used for catalyzing acetyl ammoniation reaction of the adamantane, nickel and rhodium are in synergistic effect, the catalytic activity is enhanced, reaction is facilitated to proceed, meanwhile, occurrence of side effects is inhibited, and the yield of a target product is increased; a bromine raw material is prevented from being used, corrosion of bromine to equipment and pollution of the bromineto environment can be avoided, the environmental protection property is good, and the synthetic method is mild in condition, simple and feasible in technology and high in product yield.
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Paragraph 4-6
(2019/02/17)
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- Synthesis of N-(Adamantan-1-yl)carbamides by Ritter Reaction from Adamantan-1-ol and Nitriles in the Presence of Cu-Catalysts
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A selective synthesis of (Z)-N-(adamantan-1-yl)carbamides by the reaction of adamantan-1-ol and nitriles in the presence of Cu catalysts was carried out. Z-Conformation of amides is established basing on X-ray diffraction analysis and 2D NMR data.
- Bayguzina,Lutfullina,Khusnutdinov
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p. 1127 - 1133
(2018/10/24)
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- Stereospecific sp3 C–H oxidation with m-CPBA: A CoIII Schiff base complex as pre-catalyst vs. its CoIIICdII heterometallic derivative
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The mono- and binuclear Schiff base complexes [CoL3]·DMF (1) and [CoCdL3Cl2]·0.5H2O (2) were facilely synthesized using zerovalent cobalt and cadmium chloride (for 2) as starting materials and the pre-formed pro-ligand HL (2-methoxy-6-[(methylimino)methyl]phenol, the product of condensation of o-vanillin and methylamine) in air. The compounds were characterized by single crystal X-ray diffraction analysis and spectroscopic methods in solution and in the solid state. Both complexes demonstrate a profound catalytic activity in the stereoselective oxidation of cis-1,2-dimethylcyclohexane (model substrate) with m-CPBA (m-chloroperbenzoic acid) under mild conditions in the presence of promoters of various acidity (HNO3, TFA and HOAc). The heterometallic binuclear CoIIICdII pre-catalyst (2) was more active than the mononuclear CoIII one (1), exhibiting higher products yields up to 51% and excellent stereospecificity (up to 99.2% retention of stereoconfiguration). This result could be associated with a synergistic effect of two different metals in 2. Based on the large obtained kinetic isotope effect and H218O labeling studies, the overall reaction mechanism was proposed to proceed without the participation of free alkyl radicals. The acidity of the promoter was shown to influence catalytic parameters for both 1 and 2 so that the better parameters are achieved with the acid possessing lower pKa values (a stronger acid). The comparison of the catalytic behaviours of 1 and 2 is discussed in detail considering relevant examples from the literature.
- Nesterova, Oksana V.,Kasyanova, Katerina V.,Makhankova, Valeriya G.,Kokozay, Vladimir N.,Vassilyeva, Olga Yu.,Skelton, Brian W.,Nesterov, Dmytro S.,Pombeiro, Armando J.L.
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p. 171 - 184
(2018/05/28)
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- Hypervalent Iodine(III)-Mediated Decarboxylative Ritter-Type Amination Leading to the Production of α-Tertiary Amine Derivatives
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α-Tertiary amines (ATAs) are attractive structural motifs that are frequently found in biologically active molecules. Therefore, the development of an efficient method for the synthesis of ATAs represents an important research topic in the field of medicinal chemistry as well as organic chemistry. Although the Ritter reaction is a reliable approach for preparing α-tertiary amine derivatives via intermolecular amination reactions, the typical methods suffer from disadvantages such as harsh reaction conditions and the use of strong acids. Because of this, it has been of limited use in the synthesis of ATAs. We report here on the decarboxylative Ritter-type amination of carboxylic acids bearing an α-quaternary carbon center using a combination of PhI(OAc)2 and molecular iodine (I2) to produce the corresponding α-tertiary amine derivatives. This reaction proceeded at ambient temperature on the benchtop with a fluorescent light. Mechanistic investigations suggest that the reaction proceeds via the formation of an alkyl iodide and a higher oxidation state iodine(III) species as key intermediates. Similarly, a stepwise protocol for the Ritter-type amination of alcohols via the formation of oxalic acid monoalkyl esters was also achieved. The present methods represent a useful tool for the synthesis of ATAs that are difficult to prepare by conventional methods.
- Kiyokawa, Kensuke,Watanabe, Tomoki,Fra, Laura,Kojima, Takumi,Minakata, Satoshi
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p. 11711 - 11720
(2017/11/27)
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- An Improved Synthesis of Amantadine Hydrochloride
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Amantadine hydrochloride 1 is an antiviral drug used in the prevention and treatment of influenza A infections. It has also been used for alleviating early symptoms of Parkinson's disease. Several methods for the preparation of 1 have been reported. These procedures started with adamantane 2 using as many as four reaction steps to produce amantadine hydrochloride with overall yields ranging from 45% to 58%. In this article, we describe a two-step procedure for the synthesis of 1 from 2 via N-(1-adamantyl)acetamide 4 with an improved overall yield of 67%. The procedure was also optimized to reduce the use of toxic solvents and reagents, rendering it more environment-friendly. The procedure can be considered as suitable for large-scale production of amantadine hydrochloride. The structure of amantadine hydrochloride was confirmed by 1H NMR, 13C NMR, IR, and MS.
- Vu, Duong Binh,Nguyen, Thinh Van,Le, Son Trung,Phan, Chau DInh
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supporting information
p. 1758 - 1760
(2017/11/28)
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- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
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Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
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p. 13653 - 13667
(2017/03/11)
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- Indium-Triflate-Catalyzed Ritter Reaction in Liquid Sulfur Dioxide
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The use of liquid sulfur dioxide as a reaction solvent facilitates the Ritter reaction between alcohols and nitriles. In(OTf)3 was found to be a viable catalyst for this transformation. The newly developed catalytic conditions for the Ritter reaction were successfully applied to the synthesis of various amides, which were formed in good to excellent yields. The catalytic activation of secondary alcohols for Ritter reactions in liquid sulfur dioxide was also found to be effective.
- Posevins, Daniels,Suta, Krista,Turks, Maris
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supporting information
p. 1414 - 1419
(2016/03/19)
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- A 1-amide base Jin'gang alkane method for the preparation of
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The invention discloses a preparation method of 1-amide adamantine. The method comprises the steps that: 1, trifluoroacetic acid is adopted as a solvent, under the existence of oxygen, and under the effect of sodium nitrite, a compound represented by the formula I is subjected to an oxidation reaction, wherein a reaction temperature is 10-35 DEG C; 2, the reaction liquid obtained in the step 1 is mixed with RCN or RCONH2, and a reaction is carried out, such that a compound represented by the formula II is obtained, wherein a reaction temperature is 60-80 DEG C, and R is hydrogen, methyl, ethyl or C3-C5 cycloalkyl. The preparation method provided by the invention has the advantages of mild reaction condition, simple operation, less side product, simple post-treatment, and suitability for industrialized productions. With the method, high-yield and high-purity 1-amide adamantine can be prepared.
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Paragraph 0035; 0036
(2017/02/28)
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- Novel technology for preparing 1-acetamidodamantane
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The invention discloses a novel technology for preparing 1-acetamidodamantane. Oleum which is environment-friendly, low in harm to human bodies and simple to control and adopts the looser control standard is used for replacing a halogen (bromine) used in the traditional technology; other raw materials mainly include adamantane, acetonitrile, dichloromethane and alkaline water; compared with the traditional technology for preparing 1-acetamidodamantane, the technology can increase the yield; particularly, the adamantane is added in batches, about 1/4 of the adamantane is added after the temperature gets close to the room temperature, the reaction progress can be better controlled, acid and the acetonitrile can be utilized to the maximum extent, the ingredient proportion of the adamantane is increased, and the yield per unit is increased.
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Paragraph 0028-0037
(2016/10/07)
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- Process for preparing amantadine free amine by using amantadine hydrochloride
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The invention discloses a process for preparing amantadine free amine by using amantadine hydrochloride. The process is characterized by being operated according to the following steps of first adding water and amantadine hydrochloride according to the mass ratio being 1:4 into a reaction still; after uniformly stirring, adjusting the pH value to be 10 by using sodium hydroxide or sodium carbonate; after a solid is separated out, continuously stirring for 0.5h, filtering, washing and drying to obtain an amantadine free amine pure product.
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Paragraph 0048-0056
(2016/12/16)
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- Ritter-type amination of C-H bonds at tertiary carbon centers using iodic acid as an oxidant
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The Ritter-type amination of a tertiary C-H bond using iodic acid (HIO3) as an oxidant, in the presence of N-hydroxyphthalimide (NHPI) is reported. This operationally simple method is conducted under metal-free conditions, is scalable, and efficiently provides valuable α-tertiary amine derivatives.
- Kiyokawa, Kensuke,Takemoto, Kenta,Minakata, Satoshi
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supporting information
p. 13082 - 13085
(2016/11/09)
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- Direct Preparation of Amides from Amine Hydrochloride Salts and Orthoesters: A Synthetic and Mechanistic Perspective
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The conversion of a wide range of primary and secondary aliphatic and a few arylamine hydrochloride salts to their corresponding acetamides with trimethyl orthoacetate is described. Mechanistic studies using NMR and gas chromatography-mass spectrometry techniques indicate these reactions proceed via an O-methylimidate intermediate that undergoes in situ demethylation by chloride, affording the corresponding acetamides. Synthetically, this reaction represents a practical, high-yielding protocol with a simple workup for the rapid conversion of amine hydrochloride salts to acetamides.
- Di Grandi, Martin J.,Bennett, Caitlin,Cagino, Kristen,Muccini, Arnold,Suraci, Corey,Saba, Shahrokh
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supporting information
p. 2601 - 2607
(2015/11/28)
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- Catalytic N-Alkylation of Amines Using Carboxylic Acids and Molecular Hydrogen
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A convenient, practical and green N-alkylation of amines has been accomplished by applying readily available carboxylic acids in the presence of molecular hydrogen. Applying an in situ formed ruthenium/triphos complex and an organic acid as cocatalyst, a broad range of alkylated secondary and tertiary amines are obtained in good to excellent yields. This novel method is also successfully applied for the synthesis of unsymmetrically substituted N-methyl/alkyl anilines through a direct three-component coupling reaction of the corresponding amines, carboxylic acids, and CO2 as a C1 source.
- Sorribes, Iván,Cabrero-Antonino, Jose R.,Vicent, Cristian,Junge, Kathrin,Beller, Matthias
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supporting information
p. 13580 - 13587
(2015/11/10)
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- Synthesis of N-(adamantan-1-yl)amides by reaction of carboxylic acid amides with 1-bromo(chloro)adamantane catalyzed by manganese compounds
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Abstract N-(Adamantan-1-yl)amides were synthesized in 70-90% yield by reaction of 1-bromoadamantane with carboxylic acid amides in the presence of manganese salts and complexes.
- Khusnutdinov,Shchadneva,Khisamova
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p. 476 - 479
(2015/05/27)
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- Microwave assisted, Ca(II)-catalyzed Ritter reaction for the green synthesis of amides
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An efficient solvent-free synthesis of amides by Ca(II) catalyzed Ritter reaction has been reported under microwave irradiation. This green protocol tolerates the substrate diversity and delivers the high yielding amides with minimal loading of inexpensive and more abundant Ca(II) catalyst.
- Yaragorla, Srinivasarao,Singh, Garima,Lal Saini, Pyare,Reddy, M. Kesava
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p. 4657 - 4660
(2014/12/10)
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- Alcohols as electrophiles: Iron-catalyzed Ritter reaction and alcohol addition to alkynes
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A simple, iron-based catalytic system allows for a straightforward method for the synthesis of primary, secondary, and tertiary amides. The system also allows the addition of benzyl alcohols across phenylacetylene to produce substituted phenyl ketones. This transformation improves and expands the substrate scope beyond that previously reported and proceeds under mild reaction conditions, tolerating air and moisture.
- Jefferies, Latisha R.,Cook, Silas P.
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supporting information
p. 4204 - 4207
(2014/06/09)
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- Ritter reactions between alcohols and acetonitrile mediated by the conducting polymer poly-(3,4-ethylenedioxy thiophene) (Pedot)
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Herein, we report new reactivity of the conducting polymer, poly-(3,4-ethylenedioxy thiophene) (PEDOT), where PEDOT mediates a Ritter reaction between alcohols and acetonitrile. The yields were variable and in most cases competitive with results obtained using sulfuric acid. Attempts at a stoichiometric reaction between benzonitrile and diphenylmethanol are also reported herein. Finally, described here are preliminary mechanistic studies that suggest PEDOT is behaving as an alcohol-selective or specific Lewis acid. Taylor & Francis Group, LLC.
- D-Angelo, John G.,Cody, Jeremy A.,Larrabee, Christian,Ostrander, Danica J.,Rugg, Kyle W.,Mamangun, Donna
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supporting information
p. 3224 - 3232
(2014/01/06)
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- Highly efficient synthesis of amides via Ritter chemistry with ionic liquids
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The utility of Br?nsted-acidic imidazolium ionic liquid [BMIM(SO3H)][OTf] as catalyst for the high yield synthesis of a wide variety of amides under mild conditions via the Ritter reaction of alcohols with nitriles has been demonstrated. As alternative methods for the carbocation generation step, NOPF6 immobilized in [BMIM][PF6] ionic liquid was used in the Ritter reaction of bromides with nitriles and for the synthesis of adamantyl amides from adamantane and nitriles.
- Kalkhambkar, Rajesh G.,Waters, Sarah N.,Laali, Kenneth K.
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supporting information; experimental part
p. 867 - 871
(2011/03/18)
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- Ritter reaction of organic nitriles with 1-bromo- and 1-hydroxyadamantanes catalyzed by manganese compounds and complexes
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Manganese compounds and complexes [MnCl2, MnBr2, Mn(OAc)2, Mn(acac)2, Mn(acac)3, Mn 2(CO)10] catalyze Ritter reaction of organic nitriles with 1-bromo- and 1-hydroxyadamantanes. The reaction proceeds in water environment in the absence of acids at 100-130°C over 3-5 h and affords N-(adamantan-1-yl)amides in 75-100% yields.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Khisamova,Dzhemilev
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experimental part
p. 1682 - 1685
(2012/03/09)
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- Effective oxidation of benzylic and alkane C-H bonds catalyzed by sodium o-iodobenzenesulfonate with Oxone as a terminal oxidant under phase-transfer conditions
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Catalytic oxidation of benzylic C-H bonds could be efficiently realized using IBS as a catalyst which was generated in situ from the oxidation of sodium 2-iodobenzenesulfonate (1b) by Oxone in the presence of a phase-transfer catalyst, tetra-n-butylammonium hydrogen sulfate, in anhydrous acetonitrile at 60 °C. Various alkylbenzenes, including toluenes and ethylbenzenes, several oxygen-containing functionalities substituted alkylbenzenes, and a cyclic benzyl ether could be efficiently oxidized. And, the same reagent system of cat. 1b/Oxone/cat. n-Bu4NHSO4 could be applied to the effective oxidation of alkanes as well.
- Cui, Li-Qian,Liu, Kai,Zhang, Chi
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experimental part
p. 2258 - 2265
(2011/05/08)
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- Polyvinylpolypyrrolidone-supported boron trifluoride: A high-loaded, polymer-supported Lewis acid for the Ritter reaction
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A Mild and efficient method for preparing amides by reaction of nitriles with benzhydrol and tertiary alcohols is described using polyvinylpolypyrrolidone-supported boron trifluoride. Selective amidation of benzhydrol in the presence of primary benzyl alcohols was also achieved.
- Lakouraj, Moslem Mansour,Mokhtary, Masoud
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experimental part
p. 53 - 56
(2010/03/30)
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- γ-aminoadamantanecarboxylic acids through direct C-H bond amidations
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Utilizing bromine-free, direct C-H bond amidations we have synthesized a large variety of adamantane amides. Depending on the precursors used these amides directly yield pharmaceutically active aminoadamantanes or γ-aminoadamantanecarboxylic acids after hydrolytic cleavage. These rigid analogues of γ-aminobutyric acid (GABA) were protected at the C- and N-termini and we synthesized a number of peptides incorporating γ-aminoadamantanecarboxylic acids in solution as well as via solid phase peptide synthesis. These peptides are promising scaffolds for applications in medicinal chemistry as well as in organocatalysis. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Wanka, Lukas,Cabrelle, Chiara,Vanejews, Maksims,Schreiner, Peter R.
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p. 1474 - 1490
(2008/09/19)
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- A convenient protocol for C-H oxidation mediated by an azido radical culminating in Ritter-type amidation
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Cerium(IV) ammonium nitrate in combination with sodium azide reacts with unactivated hydrocarbons in acetonitrile to furnish acetamides in one pot. The strategy can be used to introduce nitrogen functionality into a variety of compounds; a carboxylic ester directly afforded the corresponding α-amino acid.
- Nair, Vijay,Suja,Mohanan, Kishor
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p. 3217 - 3219
(2007/10/03)
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- Titanium dioxide photocatalysis of adamantane
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TiO2 photocatalysis of adamantane in oxygen equilibrated MeCN yields 1- and 2-adamantanol and adamantanone with limited degradation and preference for functionalization at the 1 position, particularly in the presence of silver salts. Oxidation in CH2Cl2 is less selective. The oxidation of cyclohexane and cyclododecane is slower. In N2-flushed solutions with Ag+ as a sacrificial acceptor, products from the trapping of both 1-adamantyl radical (adamantyl methyl ketone) and cation (N-adamantylacetamide) are obtained. Furthermore, alkylation of an electrophilic alkene (isopropylydenmalononitrile) has been obtained, though in a low yield.
- Cermenati, Laura,Dondi, Daniele,Fagnoni, Maurizio,Albini, Angelo
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p. 6409 - 6414
(2007/10/03)
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- Selective nitrogen functionalization of organic compounds
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There is provided a method of selectively replacing a carbon-hydrogen bond at an unactivated saturated sp3 hybridised carbon atom in an organic compound by a carbon-nitrogen bond, the method comprising reacting the compound with a fluorinating agent in a solvent reaction medium comprising a nitrile compound and providing a Lewis acid whereby the carbon-hydrogen bond is replaced by a carbon-nitrogen bond. Advantageously, the reaction may be performed in one stage and/or in one vessel. Advantageously, the method may be carried out at or just below ambient or room temperature.
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- Elementalfluorine. Part 14.1 Electrophilic fluorination and nitrogen functionalisation of hydrocarbons
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Selective fluorination of a range of hydrocarbons was achieved by reaction with either elemental fluorine or Selectfluor, an electrophilic fluorinating reagent of the N-F class. An electrophilic mechanism is envisaged. On prolonged reaction, the strongly acidic reaction medium that is formed upon substitution of hydrogen by fluorine when Selectfluor is used as the fluorinating reagent, promotes loss of fluoride from the initial fluorinated product. Trapping of the subsequent carbocation by the acetonitrile solvent in a Ritter type process gives overall nitrogen functionalisation of hydrocarbons. Amidation of hydrocarbons could also be achieved in a one-stage process by reaction of the hydrocarbon with fluorine and a Lewis acid, such as boron trifluoride-diethyl ether, in acetonitrile.
- Chambers, Richard D.,Kenwright, Alan M.,Parsons, Mandy,Sandford, Graham,Moilliet, John S.
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p. 2190 - 2197
(2007/10/03)
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- Formation of adamantan-1-ols by the reactions of adamantanes with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in trifluoromethanesulfonic acid
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Adamantanes were treated with DDQ in trifluoromethanesulfonic acid followed by hydrolysis to give adamantan-1-ols in good yields.
- Tanemura,Suzuki,Nishida,Satsumabayashi,Horaguchi
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p. 3230 - 3231
(2007/10/03)
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- Oxidative alkylation of azoles: VII. Adamantylation of azoles via oxidative generation of 1-adamantyl cations
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A procedure has been developed for oxidative N-adamantylation of azoles with 1-iodoadamantane in the presence of chromium(IV) oxide or iodine(V) oxide. The procedure is applicable to azoles whose pKBH+ value does not exceed 2.26. * For communication VI, see [1].
- Tsypin,Pevzner,Golod
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p. 1762 - 1766
(2007/10/03)
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- A New Approach for Oxygenation Using Nitric Oxide under the Influence of N-Hydroxyphthalimide
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An approach for partial oxygenation through a carbocation as an intermediate was successfully developed by using nitric oxide under the influence of N-hydroxyphthalimide. Thus, a variety of benzylic ethers were converted into the corresponding partially oxidized compounds, which are difficult to prepare by conventional methods, in high yields. For example, the reaction of phthalane with NO in the presence of a catalytic amount of NHPI at 60°C gave phthalaldehyde in 80% yield. The reaction was found to proceed through the formation of a hemiacetal, such as 1-hydroxyphthalane. In addition, 1,3-di-tert-butoxymethyl benzene afforded 1,3-benzenedicarbaldehyde in good yield. On the other hand, isochroman was converted into 1,1′-oxodiisochromane under these reaction conditions. The reaction of ethers with NO in the presence of a NHPI catalyst is thought to proceed via the formation of a carbocation as an intermediate. A possible reaction path was suggested.
- Eikawa, Masahiro,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 4676 - 4679
(2007/10/03)
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- Adamantylation and adamantylalkylation of amides, nitriles, and ureas in trifluoroacetic acid
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A new preparative procedure was developed for N-adamantylation of carboxylic acids amides and ureas, and C5-adamantylation of barbituric acid in trifluoroacetic acid medium with tertiary adamantanols and 1-adamantylalkanols. The reaction of 2-adamantanols and secondary 1-adamantylalkanols with nitriles was for the first time used in the preparation of W-(2-adamantyl)-and N-(1-adamantylalkyl)amides.
- Shokova,Musulu, Tasula,Luzikov,Kovalev
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p. 844 - 856
(2007/10/03)
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- Adamantylation and adamantylalkylation of amides, nitriles and ureas in trifluoroacetic acid
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A new preparative method for N-adamantylation of carboxylic acid amides, ureas and for C5-adamantylation of barbituric acid in trifluoroacetic acid (TFA) is proposed. Tertiary 1-adamantanols and 1-(1-adamantyl)alkanols were used as adamantylating agents. The reaction of 1-(1-adamantyl)alkanols with nitriles in TFA solution was employed for the first time for the preparation of N-[1-(1-adamantyl)alkyl]amides.
- Shokova, Elvira,Mousoulou, Tasoulla,Luzikov, Yurij,Kovalev, Vladimir
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p. 1034 - 1040
(2007/10/03)
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- N-Hydroxyphthalimide (NHPI)-catalyzed reaction of adamantane under nitric oxide atmosphere
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The reaction of adamantane under atmospheric nitric oxide in the presence of N-hydroxyphthalimide (NHPI) which serves as the radical catalyst in a mixed solvent of benzonitrile and acetic acid afforded 1-N-adamantylbenzamide as a principal product along with small amounts of 1-nitroadamantane and 1-hydroxyadamantane. On the other hand, 1-nitroadamantane was obtained in good yield upon treatment of adamantane with NO/O2.
- Sakaguchi, Satoshi,Eikawa, Masahiro,Ishii, Yasutaka
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p. 7075 - 7078
(2007/10/03)
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- Oxidative functionalization of adamantane and some of its derivatives in solution
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1,2,4,5-Benzenetetracarbonitrile (TCB) is irradiated in the presence of adamantane (1) and some of its derivatives. The singlet excited state of TCB is a strong oxidant, and there is various evidence, including time-resolved spectroscopy, to prove that SET from the alkane to TCB1* takes place and yields the corresponding radical ions. The adamantane radical cation deprotonates from the bridgehead position, and the resulting radical couples with TCB-*. Deprotonation via the radical cation occurs with a number of substituted adamantanes and remains the exclusive or predominating reaction also with derivatives containing a potential electrofugal group, such as one of the following carbocations: t-Bu, CH2OMe, CH2OH (notable here is that C-H deprotonation is more efficient than O-H deprotonation). A carboxy group is lost more efficiently than a proton, however. In contrast, detaching of such cations is the main process when the radical cations of substituted adamantanes is produced anodically. This different behavior is explained on the basis of thermochemical calculation and of the different environments experienced by the radical cation in the two cases, viz reaction from the solvated radical cation in the first case and from the substrate adsorbed on the anode in the latter one. 1-Methoxyadamantane deprotonates from the methyl group, a reaction explained by the different structure of the radical cation. On the other hand, the radical NO3*, conveniently produced by photolysis of cerium(IV) ammonium nitrate, reacts by hydrogen abstraction with selective attack at the bridgehead position and little interference by substituents and thus offers a useful way for the selective oxidative functionalization of adamantanes.
- Mella,Freccero,Soldi,Fasani,Albini
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p. 1413 - 1420
(2007/10/03)
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- The photochemical approach to the functionalization of open-chain and cyclic alkanes: 2. Hydrogen abstraction
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Chloranil (Chl) has been irradiated in the presence of the alkanes 2,3-dimethylbutane, cyclohexane, norbornane, adamantane in acetonitrile. The primary step is hydrogen abstraction by triplet Chl, k(H) 0.8 to 2 x 106 M-1s-1, as confirmed by the detection of the ChlH. radical. Hydrogen abstraction from the alkanes is unselective. The thus formed alkyl radicals undergo different reaction, viz: coupling with ChlH· (both C-O coupling to give hydroquinonemonoethers and C-C coupling to give hydroxydihydrobenzofurans are observed); addition to ground state Chl to yield ultimately alkoxyphenoxyquinones; oxidation by groud state Chl (this process is fast only with tertiary radicals, and the cations formed in this case are trapped by the solvent MeCN to yield acetamides). Different methods for alkane functionalization are compared.
- Mella, Mariella,Freccero, Mauro,Albini, Angelo
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p. 5549 - 5562
(2007/10/03)
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- Photoinduced SET for the Functionalization of Alkanes
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Thermochemical cycles show that deprotonation of alkane radical cations is an exothermic process, and indeed photoinduced SET between several alkanes and 1,2,4,5-tetracyanobenzene (TCB) is followed by efficient deprotonation of the radical cation with tertiary > secondary > primary selectivity; the alkyl radical is trapped by TCB.- or, when present, by oxygen; when tetrachloro-p-benzoquinone is used in the place of TCB, the radical is further oxidized to the cation.
- Mella, Mariella,Freccero, Mauro,Albini, Angelo
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- Azodioxide radical cations
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This report provides the first examples of solution-stable azodioxide radical cations and describes their direct spectroscopic observation and, in one case, their thermal chemistry. The formal oxidation potentials, Eo′, for N,N′-dioxo-2,3-diazabicyclo[2.2.2]oct-2-ene (3), N,N′-dioxo-2,3-diazabicyclo[2.2.1]hept-2-ene (4), and N,N′-dioxo-1,1′-azobis(norbornane) (5) are 1.65, 1.68, and 1.54 V vs SCE, respectively. ESR spectroscopy shows the intermediate cations to be π radicals. Radical cation 5?+ (red, λm 510 nm) has a five-line ESR spectrum of a(2N) 1.1 G, while 3?+ (bronze) has a nine-line ESR spectrum simulated as a(4H) 0.86 and a(2N) 1.22 G. Both 3?+ and 5?+ decay in seconds to minutes at room temperature. Thermal decomposition of 5?+ results in C,N and N,N bond cleavage, yielding 1-norbornyl cation (trapped by solvent) and NO+ (trapped in low yield by the oxidant under chemical oxidation conditions). Two viable mechanisms are presented for 5?+'s thermal decay, both of which invoke nitrosoalkane monomer 5m as an intermediate. In a related study, oxidation of nitrosoalkane 2m is found to mediate its facile denitrosation. This work affords the first examples of electron-transfer-mediated C,N bond cleavage of azodioxides and of nitrosoalkanes. Substantial bond weakening is shown to accompany electron loss from these substrates. For 5, π oxidation leads ultimately to σ C,N bond activation.
- Greer, Melinda L.,Sarker, Haripada,Mendicino, Maria E.,Blackstock, Silas C.
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p. 10460 - 10467
(2007/10/03)
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- Dissociative electron transfer to dihaloalkanes. electrochemical reduction of 1,3-dihaloadamantanes, 1,4-dihalobicyclo[2.2.2]octanes, and 1,3-dihalobicyclo[1.1.1]pentanes
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The electrochemical reductive cleavage of the title compounds was investigated by means of cyclic voltammetry and electrolysis. The reaction is a two-electron process that yields competitively ring closure (or fragmentation) products and the monohalide resulting from the expulsion of the best leaving halide ion. Product selection occurs at the level of the carbanion resulting from the reduction of the one-electron reductive cleavage radical. In the formation of the latter, electron transfer and bond breaking are concerted; thus, the anion radical is not involved as an intermediate. The variations in the reduction potential observed in the three series of compounds can be rationalized, by application of the dissociative electron-transfer theory, as related variations of the bond dissociation energy of the first carbon-halogen bond to be cleaved. In the adamantane and bicyclopentane series, these are mainly the result of through-space-bonded interactions in the one-electron reductive cleavage radical and, to a lesser extent, in the starting dihalide itself, while through-bond interactions appear to prevail in the bicyclooctane series.
- Adcock, William,Clark, Christopher I.,Houmam, Abdelaziz,Krstic, Alexander R.,Pinson, Jean,Savéant, Jean-Michel,Taylor, Dennis K.,Taylor, Julian F.
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p. 4653 - 4659
(2007/10/02)
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