- Copper-Catalyzed Intermolecular Functionalization of Unactivated C(sp3)-H Bonds and Aliphatic Carboxylic Acids
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Intermolecular functionalization of C(sp3)-H bonds and aliphatic carboxylic acids enables the efficient synthesis of high value-added organic compounds from readily available starting materials. Although methods involving hydrogen atom transfer have been developed for such functionalization, these methods either work for only activated C(sp3)-H bonds or bring in a narrow set of functional groups. Here we describe a Cu-catalyzed process for the diverse functionalization of both unactivated C(sp3)-H bonds and aliphatic carboxylic acids. The process is enabled by the trapping of alkyl radicals generated through hydrogen atom abstraction by arylsulfonyl-based SOMO-philes, which introduces a large array of C, N, S, Se, and halide-based functional groups. The chemoselectivity can be switched from C-H functionalization to decarboxylative functionalization by matching the bond dissociation energy of the hydrogen atom transfer reagent with that of the target C-H or O-H bond.
- Mao, Runze,Bera, Srikrishna,Turla, Aurélya Christelle,Hu, Xile
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supporting information
p. 14667 - 14675
(2021/09/18)
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
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- Dealkenylative Thiylation of C(sp3)-C(sp2) Bonds
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Carbon-carbon bond fragmentations are useful methods for the functionalization of molecules. The value of such cleavage events is maximized when paired with subsequent bond formation. Herein we report a protocol for the cleavage of an alkene C(sp3)-C(sp2) bond, followed by the formation of a new C(sp3)-S bond. This reaction is performed in nonanhydrous solvent and open to the air, employs common starting materials, and can be used to rapidly diversify natural products.
- Smaligo, Andrew J.,Kwon, Ohyun
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supporting information
p. 8592 - 8597
(2019/10/14)
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- CATALYTIC C-X-BOND METATHESIS THROUGH ARYLATION
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The present invention refers to a process for a catalytic aryl transfer to rearrange the backbone of aromatic C-X bonds.
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Page/Page column 9; 17
(2018/09/28)
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- Nickel Phosphite/Phosphine-Catalyzed C-S Cross-Coupling of Aryl Chlorides and Thiols
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A method for the coupling of aryl chlorides and thiophenols using an air-stable nickel(0) catalyst is described. This thioetherification procedure can be effectively applied to a range of electronically diverse aryl/heteroaryl chlorides without more expensive metal catalysts such as palladium, iridium, or ruthenium. This investigation also illustrates both, a variety of thiol coupling partners and, in certain cases, the use of Cs2CO3.
- Jones, Kieran D.,Power, Dennis J.,Bierer, Donald,Gericke, Kersten M.,Stewart, Scott G.
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supporting information
p. 208 - 211
(2018/01/17)
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- Catalytic B(C6F5)3[rad]H2O-promoted defluorinative functionalization of tertiary aliphatic fluorides
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A B(C6F5)3[rad]H2O-catalyzed defluorinative functionalization of tertiary aliphatic fluorides is described that proceeds under benign reaction conditions. The synthetic utility of the method is exemplified throu
- Dryzhakov, Marian,Richmond, Edward,Li, Guang,Moran, Joseph
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- A comparative study of Cu(II)-assisted vs Cu(II)-free chalcogenation on benzyl and 2°/3°-cycloalkyl moieties
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A relative synthetic strategy toward intermolecular oxidative C -Chalcogen bond formation of alkanes has been illustrated using both Cu(II) assisted vs Cu(II) free conditions. This led to construction of a comparative study of hydrocarbon benzylic and 2°/ 3°-cycloalkyl moieties bond sulfenylation and selenation protocol by the chalcogen sources, particularly sulfur and selenium, respectively. In addition, this protocol disclosed the auspicious formation of sp3 C-S coupling products over leading the sp3 C-N coupling products by using 2-mercaptobenzothiazole (MBT) substrates.
- Sahoo, Santosh K
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p. 2151 - 2157
(2016/01/12)
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- Silver-mediated decarboxylative C-S cross-coupling of aliphatic carboxylic acids under mild conditions
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A silver-mediated decarboxylative C-S cross-coupling reaction of aliphatic carboxylic acid is described. This reaction occurs smoothly under mild conditions and shows good tolerance of functional groups. It provides an alternative approach for the synthesis of alkyl aryl sulfides.
- Wang, Peng-Fei,Wang, Xiao-Qing,Dai, Jian-Jun,Feng, Yi-Si,Xu, Hua-Jian
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supporting information
p. 4586 - 4589
(2015/01/08)
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- Syntheses of sulfides and selenides through direct oxidative functionalization of C(sp3)-H bond
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A new protocol for C-S and C-Se bond formation by the direct functionalization of the C(sp3)-H bond of alkanes under metal-free conditions was developed. Using tBuOOtBu as the oxidant, the reaction of disulfides or diselenides with alkanes gave sulfides or selenides in moderate to good yields. The method was very simple and atom-economical.
- Du, Bingnan,Jin, Bo,Sun, Peipei
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supporting information
p. 3032 - 3035
(2014/06/23)
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- Synthesis of substituted adamantylzinc reagents using a Mg-insertion in the presence of ZnCl2 and further functionalizations
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The LiCl-mediated Mg-insertion in the presence of ZnCl2 allows an efficient synthesis of adamantylzinc reagents starting from the corresponding functionalized tertiary bromides. The highly reactive adamantylzinc species readily undergo a broad
- Saemann, Christoph,Dhayalan, Vasudevan,Schreiner, Peter R.,Knochel, Paul
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p. 2418 - 2421
(2014/05/20)
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- Synthesis of a wide range of thioethers by indium triiodide catalyzed direct coupling between alkyl acetates and thiosilanes
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An indium triiodide-catalyzed substitution of the acetoxy group in alkyl acetates with thiosilanes provides access to a variety of thioethers. The method is efficient for a wide scope of acetates such as primary alkyl, secondary alkyl, tertiary alkyl, allylic, benzylic, and propargylic acetates.
- Nishimoto, Yoshihiro,Okita, Aya,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 1846 - 1849
(2012/06/18)
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- Silylboranes as new sources of silyl radicals for chain-transfer reactions
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Various silylboranes, which were outfitted with a catecholborane moiety at one end and a (Me3Si)3Si moiety at the other end of a carbon chain, were prepared through the hydroboration of the corresponding unsaturated silanes. The C-ce
- Rouquet, Guy,Robert, Frederic,Mereau, Raphaal,Castet, Frederic,Renaud, Philippe,Landais, Yannick
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p. 940 - 950
(2012/02/16)
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- Synthesis of sulfides under solvent- and catalyst-free conditions
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A simple, highly efficient, and green protocol has been developed for preparation of sulfides from alkyl or aryl thiols and benzyl-, allyl-, t-butyl, and adamantyl halides under solvent- and catalyst-free conditions.
- Movassagh, Barahman,Soleiman-Beigi, Mohammad
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experimental part
p. 409 - 411
(2010/05/01)
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- Indium-mediated cleavage of diphenyl diselenide and diphenyl disulfide: efficient one-pot synthesis of unsymmetrical diorganyl selenides, sulfides, and selenoesters
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A convenient and efficient method was developed for the synthesis of alkyl phenyl selenides, sulfides, and selenoesters in one-pot reaction by using indium metal. The reaction showed the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides. For the reaction of primary and secondary alkyl iodides and bromides, the yields of selenides were improved by the addition of a catalytic amount of iodine.
- Munbunjong, Wanida,Lee, Eun Hwa,Ngernmaneerat, Poonlarp,Kim, Sung Jun,Singh, Gurpinder,Chavasiri, Warinthorn,Jang, Doo Ok
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experimental part
p. 2467 - 2471
(2009/08/15)
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- ZrCl4 dispersed on dry silica gel provides a useful reagent for S-alkylation of thiols with alcohols under solvent-free conditions
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ZrCl4 which is commercially available and not a costly compound, is a relatively safe chemical [LD50 [ZrCl4, oral rat] = 1688 mg Kg]. In this report we describe the use of ZrCl4 dispersed on dry silica gel as an efficient reagent for the efficient preparation of thioethers from thiols with alcohols under solvent-free conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Jafarpour, Maasoumeh
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- Tin-free radical carbonylation: Thiol ester synthesis using alkyl allyl sulfone precursors, phenyl benzenethiosulfonate, and CO
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(Chemical Equation Presented) Remove contents from tin ... Thiol esters have been successfully synthesized through tin-free radical carbonylation (see scheme; V-40 = initiator). This approach can be further extended to sequential radical reactions involving cyclization, carbonylation, and trapping of acyl radicals by phenyl benzenethiosulfonate.
- Kim, Sangmo,Kim, Sunggak,Otsuka, Noboru,Ryu, Ilhyong
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p. 6183 - 6186
(2007/10/03)
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- Radical reaction of S-phenyl chlorothioformate with alkyl iodides: Free radical-mediated carboxylation approach
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Free radical-mediated carboxylation is achieved by treatment of alkyl iodides with S-phenyl chlorothioformate and bis(tributyltin) with irradiation at 300 nm.
- Kim, Sunggak,Jon, Sang Yong
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p. 815 - 816
(2007/10/03)
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- Nonchain processes in nucleophilic substitutions triggered by electron transfer (SRN1). Photochemical and electrochemical induction of the substitution of 1-iodoadamantane by arenethiolate ions
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Photochemical induction of the reaction of 1-iodoadamantane with arenethiolate ions provides a clear-cut example of nonchain SRN1 substitutions. With 4-methoxy-, 4-methyl-, and 4-cyanobenzene and benzenethiolate ions, excellent yields (over 85%) are obtained in spite of efficient electron transfer quenching of the very easily oxidized anion radical of the substituted product by quaternary ammonium countercations. The production of the corresponding disulfides is used to determine the number of chains. Absorption and fluorescence spectroscopy and laser pulse irradiation experiments indicate that the electron which triggers the substitution process is generated by photoejection from the nucleophile, with an efficiency that decreases in the order 4-methoxybenzene > 4-methyl-benzene > 4-benzene > 4-cyanobenzenethiolate. Electron photoejection does not occur with naphthalenethiolate ions. However substitution can be entrained by addition of benzenethiolate ions. The two nucleophiles were found to have comparable reactivities toward the 1-adamantyl radical. Rather than the formation of its anion radical, the first step of the SRN1 process is a dissociative electron transfer to 1-iodoadamantane, yielding directly the adamantyl radical. This is the reason that direct electrochemical induction of the substitution was not observed. Induction by electrogenerated aromatic anion radicals could be observed. It was much less efficient than photoinduction because the amount of electron donor species required to trigger the reaction is much larger.
- Ahbala, Mustapha,Hapiot, Philippe,Houmam, Abdelaziz,Jouini, Mohamed,Pinson, Jean,Savéant, Jean-Michel
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p. 11488 - 11498
(2007/10/03)
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- Preparation of adamantyl sulfides with [bis(1-adamantanecarboxy)iodo]arenes and disulfides
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Irradiation of [bis(1-adamantanecarboxy)iodo]arenes with a high-pressure mercury lamp in the presence of disulfides gives the corresponding adamantyl sulfides in high yields. This reaction proceeds via the radical decarboxylation of [bis(1-adamantanecarbo
- Togo,Muraki,Yokoyama
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p. 155 - 157
(2007/10/02)
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- Photochemistry of phenyl thioethers and phenyl selenoethers. Radical vs ionic behavior
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In analogy with alkyl iodides and bromides, the phenyt thio- and selenoethers 2a,b, 13a, 21b,c and 35 displayed competing radical and ionic photobehavior on irradiation in solution, via a mechanism thought to involve initial homolytic cleavage of the alkyl C-S or C-Se bond followed by electron transfer within the resulting radical pair cage (Scheme I). These are the first examples of ionic photobehavior to be recognized for the C-SAr and C-SeAr chromophores. The electronegatively substituted pentafiuorophenyl analogues 2c, 13b, and 21d displayed enhanced ionic photobehavior. By contrast, the 4-methoxyphenyl derivative 21a exhibited almost exclusively radical behavior. The sulfoxide (2R*,R*s)-21f displayed principally radical behavior, accompanied by epimerization at sulfur. The quantum yields for the disappearance of the 2-norbornyl ethers 21b and 21c were 0.53-0.64 in solution and rose to 0.89-0.95 in the presence of suspended fumed silica. Irradiation of the phenyl thioether 21b on silica gel resulted in nucleophilic trapping by surface silanol groups to afford covalently bound material (33), which afforded chloride 34 on treatment with SOCl2. Irradiation of phenyl thioethers 2a and 35, phenyl selenoether 2b, or C6H5SH in allyl alcohol solution afforded acetal 11, apparently via isomerization of some of the solvent to propanal (44) followed by acetalization. Irradiation of alcoholic solutions of aldehydes containing C6H5SH is a useful means of generating acetals under neutral conditions.
- Kropp, Paul J.,Fryxell, Glen E.,Tubergen, Mark W.,Hager, Michael W.,Harris Jr., G. Davis,McDermott Jr., T. Paul,Tornero-Velez, Rogelio
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p. 7300 - 7310
(2007/10/02)
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- Reactions of Thermally Generated tert-Butyl and Di(tert-alkyl)ketyl Radicals in Toluene: Cage Effects and Hydrogen Transfer
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Thermolysis of di(1-adamantyl)-tert-butylmethanol (2a) in toluene at 145-185 deg C gives mainly bibenzyl, di(1-adamantyl) ketone, di(1-adamantyl)methanol, and the cross-product, 1,1-di(1-adamantyl)-2-phenylethanol.In the presence of benzophenone (BP) or benzenethiols as hydrogen-accepting and hydrogen-donating radical scavengers, respectively, the di(1-adamantyl)methanol/di(1-adamantyl) ketone ratio tends to steady values as the scavenger/2a ratio is increased, while the cross-product disappears.At 165 deg C the secondary alcohol minimum is 8percent (BP) and the ketone minimum 11percent (thiol).These represent the contributions of geminate hydrogen atom transfer reactions to the overall yields, i.e., the cage effects.With BP the major cross-product is 1,1,2-tri-phenylethanol.Products from the self- and cross-reactions of benzyl and thiyl radicals are found when thiol is present, the diaryl disulfide predominating at high thiol concentration.In both cases, cross-products resulting from reaction of the tert-butyl radical with the scavenger-derived radical are detected in small amounts, being of greater importance in deuteriated toluene.The tert-butyl radical is considered, therefore, to be less reactive in hydrogen atom abstraction than the 1-adamantyl radical.Cage effects for other di(tert-alkyl)-tert-butylmethanols that thermolyze with exclusive t-Bu-C bond fission have also been measured and the product composition of the scavenger-free reaction interpreted by kinetic simulation based on the steady state approximation.Rate constants for hydrogen abstraction by the tert-butyl radical from toluene are not accurately determined by this procedure but seem, nevertheless, to indicate that the literature value (14.4 M-1s-1 at 48 deg C) is an overestimate. Solvent hydrogen abstraction by the ketyl radical shows a small but well-defined steric effect.
- Lomas, John S.,Briand, Sylvette,Fain, Dominique
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p. 166 - 175
(2007/10/02)
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- RADICAL DECARBOXYLATIVE PHOSPHORYLATION OF CARBOXYLIC ACIDS
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Thiohydroxamic carboxylic mixed anhydrides (e.g. 1) react at room temperature with (PhS)3P to give, through a decarboxylative phosphorylation reaction, the corresponding dithiophosphonates 12 in moderate yields.
- Barton, Derek H. R.,Bridon, Dominique,Zard, Samir Z.
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p. 4309 - 4312
(2007/10/02)
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- PHOTOSTIMULATED REACTIONS OF 1-IODOADAMANTANE AND IODOBENZENE WITH THIOLATE, SELENATE, AND TELLURATE IONS
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The photostimulated reaction of 1-iodoadamantane (1-IAd) with benzenethiolate ion gave the substitution product 1-adamantylphenylsulfide.With benzeneselenate ion (PhSe-) it gave three products: diphenylselenide, 1-adamantylphenylselenide and di(1-adamantyl) selenide.With benzenetellurate ions it gave the substitution product 1-adamantylphenyltelluride and diphenyltelluride, the latter is ascribed to the photodecomposition of the nucleophile.The photostimulated reaction of 1-IAd with 1-naphtaleneselenate ion only gave the substitution product without scrambling of products.The photostimulated reaction of PhI with 1-adamantaneselenate ion gave the same three products as the reaction of 1-IAd and PhSe- ion, but with different ratios of products.The reaction with 1-adamantanetellurate ion gave mainly diphenyltelluride, together with the substitution product 1-adamantylphenyltelluride.The relationship of the fragmentation rates of Ad-Z and Ph-Z bonds in radical anions of structure (1-AdZPh). were studied, and kfAdZ/kfPhZ, being Z=S is 3.7, Z=Se is 9.5 and Z=Te is 13.These results suggest that in the photostimulated reactions the products obtained depend on the energy levels of the antibonding ?* MO and the ?* MO of the C-Z(Z=S, Se and Te) bonds of the radical anion intermediate.The fragmentation rates of the radical anion intermediates depend on the energy levels of the MO'S involved.
- Palacios, Sara M.,Alonso, Ruben A.,Rossi, Roberto A.
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p. 4147 - 4156
(2007/10/02)
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