- Evidence for a 1,4-dioxy diradical as an intermediate in the thermal decomposition of 3,3-dibenzyl-1,2-dioxetane
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The thermal decomposition of 3,3-dibenzyl-1,2-dioxetane (1) in CDCl3 and CH2Cl2 solutions afforded the expected decomposition product 1,3-diphenyl-2-propanone (2) and the novel rearrangement ketone -(benzyloxy)-3-phenyl-2-propanone (3) in ratios of (73 ± 10):(27 ± 10). A plausible mechanism for the formation of ketone 3 involves homolytic cleavage of the dioxetane peroxide bond with subsequent β cleavage of the benzyl group in the 1,4-dioxy diradical and in-cage combination of the resulting radicals. Moreover, several control experiments render a benzyl radical-induced decomposition of dioxetane 1 unlikely Thus, the ratio of 2 and 3 was found to be essentially independent of the initial dioxetane concentration, and the presence of radical scavengers did not affect the product ratio and reaction rate. With the electron-rich 1,4-dioxene, the dioxetane 1 afforded the cycloadduct cis-3,3-dibenzyl-2,5,7,10-tetraoxabicyclo[4.4.0]decane (4) as major product.
- Adam, Waldemar,Heil, Markus
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- Vapor-phase synthesis of symmetric ketone from alcohol over CeO2-Fe2O3 catalysts
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Formation of 3-pentanone via oxidative dimerization of 1-propanol was investigated over CeO2-based solid solution with various metal oxides. An addition of Fe2O3 into CeO2 greatly enhanced the 3-pentanone formation, and both 1-propanol conversion and 3-pentanone selectivity were maximized at Fe content of 20 mol%. It was found that the CeO2-Fe2O3 effectively works as a catalyst for the formation of symmetric ketones such as 3-pentanone, 4-heptanone, 5-nonanone, etc.
- Kamimura, Yoichiro,Sato, Satoshi,Takahashi, Ryoji,Sodesawa, Toshiaki,Fukui, Masahiro
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- Nickel-catalyzed cyanation of aryl halides and triflates using acetonitrile: Via C-CN bond cleavage assisted by 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine
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We developed a non-toxic cyanation reaction of various aryl halides and triflates in acetonitrile using a catalyst system of [Ni(MeCN)6](BF4)2, 1,10-phenanthroline, and 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (Si-Me4-DHP). Si-Me4-DHP was found to function as a reductant for generating nickel(0) species and a silylation reagent to achieve the catalytic cyanation via C-CN bond cleavage.
- Ueda, Yohei,Tsujimoto, Nagataka,Yurino, Taiga,Tsurugi, Hayato,Mashima, Kazushi
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- Iron complexes of a bidentate picolyl-NHC ligand: Synthesis, structure and reactivity
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The synthesis, structure and reactivity of bidentate picolyl N-heterocyclic carbene (NHC) iron compounds were studied. Compounds [FeBr(HL)2]Br (1), [FeBr(HL)(HMDS)] (2) and [FeBr2(HL)] (3) (HL = 1-mesityl-3-(pyridin-2-ylmethyl)imidazol-1-ylidene, HMDS = hexamethyldisilazide) were prepared from H2LBr with suitable amounts of Fe(HMDS)2 or in situ prepared [Fe(HMDS)Br]. The deprotonation of 1 with 2 eq. of LiHMDS gave [FeL2] (4), featuring dearomatized pyridine moieties with exocyclic C-C double bonds. The protonation of 4 with 2 eq. of PPh3·HBr results in the formation of 1. Attempted deprotonation of 3 using benzyl Grignard as the base resulted in transmetalation products [FeBnBr(HL)] (5) and [FeBn2(HL)] (6). Exposure of 6 to CO resulted in the formation of diamagnetic compound [Fe(CO)3(HL)] (7) and dibenzyl ketone. Prolonged exposure of 7 to CO with heating induces pyridine dissociation, affording [Fe(CO)4(HL-κC)] (8). Treatment of compound 6 with an equimolar amount of p-methoxybenzyl bromide yielded homo- and cross-coupling products.
- Liang, Qiuming,Janes, Trevor,Gjergji, Xhoana,Song, Datong
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- Carbonylative coupling of organozinc reagents in the presence and absence of aryl iodides: Synthesis of unsymmetrical and symmetrical ketones
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The utility of the palladium(o) catalysed reaction of the iodoalanine-derived organozinc reagent 6a with functionalised aryl iodides, under a carbon monoxide atmosphere, to give protected 4-aryl-4-oxo α-amino acids 8, is illustrated by a short synthesis of L-kynurenine 4. Treatment of functionalised organozinc reagents with catalytic tetrakis(triphenylphosphine)palladium(0) under an atmosphere of carbon monoxide in the absence of any electrophile leads to the formation of symmetrical functionalised ketones 9 in good yields. This reaction is illustrated by a one-step synthesis of protected (2S,6S)-4-oxo-2,6-diaminopimelic acid 9a from commercially available compounds. It has been established that adventitious molecular oxygen plays a key role in the formation of the symmetrical ketones 9, and that rigorous exclusion of oxygen can result in substantially higher yields of ketones 8 in the cross-coupling with some aromatic iodides.
- Jackson, Richard F. W.,Turner, Debra,Block, Michael H.
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- Bismuth compounds in organic synthesis. Deprotection of ketoximes using bismuth bromide-bismuth triflate
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Ketoximes undergo deprotection in CH3CN/acetone/H2O (3:6:1) in the presence of 20-40 mol percent BiBr3/5 mol percent Bi(OTf)3. Bismuth(III) salts are relatively non-toxic, insensitive to air and inexpensive. These features coupled with the use of a relatively non-toxic solvent system make this method an attractive alternative to existing routes for deprotection of ketoximes.
- Arnold, Joshua N.,Hayes, Patrick D.,Kohaus, Robert L.,Mohan, Ram S.
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- ELCTROCHEMICAL PREPARATION AND REACTIONS OF UNMASKED ACYL-ANION SYNTHONS
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Organic halides can be converted into carbonyl compounds by electroreducing a mixture of them and Fe(CO)5 in acetonitrile first and adding an electrophile to this mixture.
- Yoshida, Kunihisa,Kunugita, Ei-ichi,Kobayashi, Masaru,Amano, Sei-ichi
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- Cathodic carbonylation. Synthesis of aliphatic aldehydes using an electroreductively generated iron-carbonyl anion
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Alkyl halides are electroreductively coupled with pentacarbonyliron to generate the acyliron complexes. After hydrolytic work-up, these anionic acyl compounds produce aldehydes in good yields. The best results were obtained with the bromide as starting halide. The first step in the formation of acyliron complexes is the direct cathodic reduction of [Fe(CO)5] to the anionic species. Synthetic and mechanistic aspects of the reaction are discussed.
- Yoshida, Kunihisa,Kuwata, Hideki
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- Mechanism of the nickel-catalyzed electrosynthesis of ketones by heterocoupling of acyl and benzyl halides
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The mechanism of the nickel-catalyzed electrosynthesis of ketones by heterocoupling of phenacyl chloride and benzyl bromide has been investigated by fast scan rate cyclic voltammetry with [Ni(bpy)2+3](BF-4)2 as the catalytic precursor (bpy = 2,2′-bipyridine). The key step is an oxidative addition of Ni0(bpy) (electrogenerated by reduction of the Ni(II) precursor) to PhCH2Br whose rate constant is found to be 10 times higher than that of PhCH2COCl. The complex PhCH2NiIIBr(bpy) formed in the oxidative addition is reduced at the potential of the NiII/Ni0 reduction by a two-electron process which affords an anionic complex PhCH2Ni0(bpy)- able to react with PhCH2COCl to generate eventually the homocoupling product PhCH2COCH2Ph. The formation of the homocoupling product PhCH2COCOCH2Ph is prevented because of the too slow oxidative addition of Ni0(bpy) to PhCH2COCl compared to PhCH2Br. The formation of the homocoupling product PhCH2CH2Ph is also prevented because PhCH2Ni0(bpy)- does not react with PhCH2Br. This explains why the electrosynthesis of the ketone can be performed selectively in a one-pot procedure, starting from an equal mixture of PhCH2COCl and PhCH2Br and a nickel catalyst ligated by the bpy ligand.
- Amatore, Christian,Jutand, Anny,Perichon, Jacques,Rollin, Yolande
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- A mechanistic model for the selective oxidation of 1,4-diols to γ-lactols by o-iodoxybenzoic acid
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The selective oxidation of 1,4-diols to γ-lactols by o-iodoxybenzoic acid occurs by a rate-limiting carbonyl-forming elimination pathway in which the carbinol proton is abstracted internally via a six-atom cyclic arrangement, which explains the observed selectivity.
- Corey,Palani, Anandan
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- Incorporation of CO and NO Ligands in the Reaction of Benzyl Bromides with Tetrabutylammonium Tricarbonylnitrosylferrate
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Reaction of benzyl bromides with tetrabutylammonium tricarbonylnitrosylferrate afforded N-benzylphenylacetamides via incorporation of CO and NO ligands accompanied with dibenzyl ketones.A noticeable substituent effect on the amide-forming reaction was observed.
- Nakanishi, Saburo,Shimizu, Yasuyo
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- Synthesis of unsymmetrical ketones by applying visible-light benzophenone/nickel dual catalysis for direct benzylic acylation
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Herein, we report a dual catalytic system for the direct benzylic C-H acylation reaction furnishing a variety of unsymmetrical ketones. A benzophenone-derived photosensitizer combined with a nickel catalyst has been established as the catalytic system. Both acid chlorides and anhydrides are able to acylate the benzylic position of toluene and other methylbenzenes. The method offers a valuable alternative to late transition metal catalyzed C-H acylation reactions.
- Krach, Patricia E.,Dewanji, Abhishek,Yuan, Tingting,Rueping, Magnus
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- Nickel catalyzed electrosynthesis of ketones from organic halides and metal carbonyls
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Ketones can be easily obtained by electroreduction in an undivided cell of an organic halide-metal carbonyl mixture using a Ni-bpy catalytic system in DMF (bpy = 2,2'-bipyridine). The process is especially well convenient for primary benzyl and alkyl halides.
- Dolhem,Ocafrain,Nedelec,Troupel
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- Alkylation of Benzene with α-Diazoketones via Cycloheptatrienyl Intermediates
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Benzyl ketones can be synthesised efficiently from benzene and α-diazoketones with sequential catalysis by rhodium(II) trifluoroacetate and trifluoroacetic acid; the process involves cycloheptatrienyl intermediates.
- McKervey, M. Anthony,Russell, D. Noel,Twohig, M. Fiona
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- Dakin-West synthesis of β-aryl ketones
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Triethylamine and 1-methylimidazole were found to be selective catalysts for the Dakin-West synthesis of diaryl ketones and aryl methyl ketones, respectively. In the 1-methylimidazole-catalyzed reaction, catalysis is due to the simultaneous formation of both an effective acylating agent, 1-acyl-3-methylimidazolium, and a base, carboxylate anion. Hydrocinnamic acid, a compound previously reported to be unreactive under Dakin-West conditions, forms 4-phenyl-2-butanone when the reaction is catalyzed by 1-methylimidazole.
- Tran, Khanh-Van,Bickar, David
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- CONCERNING THE MECHANISM OF A CYANOMETALLATE MEDIATED CARBONYLATION REACTION
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The 2- anion (I) reacts with either one or two equivalents of benzyl bromide in either water/acetone or anhydrous acetonitrile to produce mainly 1,3-diphenyl-2-propanone.Excess carbon monoxide inhibitis the reaction.These results are interpreted as indicating that I is an intermediate in the reaction of K4 with CO and PhCH2Br to form 1,3-diphenyl-2-propanone.
- Rosario, R. del,Stuhl, L. S.
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- Conversion of Aliphatic and Alicyclic Carboxylic Acids into nor-Hydroperoxides, nor-Alcohols, and nor-Oxo Derivatives using Radical Chemistry
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Radicals generated from esters of N-hydroxypyridine-2-thione react smoothly with oxygen in the presence of t-butyl thiol to furnish nor-hydroperoxides, from which the corresponding alcohols and carbonyl derivatives can be readily obtained.
- Barton, Derek H. R.,Crich, David,Motherwell, William B.
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- ACTIVATED METALLIC NICKEL IN PREPARATION OF SYMMETRICAL 1,3-DIARYLPROPAN-2-ONES FROM BENZYLIC HALIDES AND OXALYL CHLORIDES
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Oxidative addition of benzylic halides to nickel in the metallic state followed by insertion of carbon monoxide generated from alkyl oxalyl chlorides proceeded smoothly to give symmetrical 1,3-diarylpropan-2-ones in moderate yields.
- Inaba, Shin-ichi,Rieke, Reuben D.
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- Convenient laboratory method for the synthesis of symmetrical 1,3-diphenylacetone derivatives
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A practical one-pot, two-step procedure for the synthesis of symmetrical 1,3-diphenylacetone derivatives from the corresponding phenylacetate has been developed. This procedure has been demonstrated by the synthesis of 1,3-diphenylacetone at the >50-gram scale in >99% purity. Georg Thieme Verlag Stuttgart - New York.
- Romer, Duane R.
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- Preparation of polyfunctional ketones by a cobalt(II) mediated carbonylation of organozinc reagents
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Functionalized organozinc halides can be efficiently carbonylated under atmospheric pressure in the presence of cobalt(II) bromide in THF:NMP leading to polyfunctional symmetrical ketones in 56-80% yield.
- Devasagayaraj,Knochel
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- Microwave promoted rapid oxidation of alcohols using cobalt nitrate hexahydrate supported on silica gel under solvent free conditions
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A new method for oxidation of alcohols into the corresponding carbonyl compounds by treatment with cobalt nitrate hexahydrate adsorbed on silica gel is described. This reagent can be used as an effective and mild oxidizing agent for this transformation under microwave irradiation in dry media, and high yields. Over oxidation of the formed aldehydes was not observed.
- Kiasat,Kazemi,Rafati
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- Electrochemical Synthesis of Symmetrical Ketones from Acid Chlorides
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The electrochemical reduction of aroyl or arylacetyl chlorides was performed in an undivided cell fitted with a stainless steel anode and a nickel foam cathode.The electrolyses were carried out at constant current in acetonitrile as solvent, leading to the corresponding symmetrical ketones. Key words: symmetrical ketones synthesis, acid chloride electroreduction.
- Folest, Jean-Claude,Pereira-Martins, Edouard,Troupel, Michel,Perichon, Jacques
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- Organocatalyzed [3 + 2] Annulation of Cyclopropenones and β-Ketoesters: An Approach to Substituted Butenolides with a Quaternary Center
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An unprecedented organocatalyzed [3 + 2] annulation of cyclopropenones and β-ketoesters has been developed. This reaction provides a direct approach to highly substituted butenolides with a quaternary center in moderate to good yields. The preliminary mechanism study verified that the enol intermediate is crucial to the reaction outcome and the intermolecular esterification and intramolecular Michael addition process were involved.
- Li, Xuanyi,Han, Chunhua,Yao, Hequan,Lin, Aijun
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- Ni-Catalyzed Reductive Carbonylation of Alkyl Halides to Form Dialkyl Ketones Using Diphenyl Oxalate as CO Surrogate
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In this work, we disclosed that diphenyl oxalate serves as a CO surrogate to enable a Ni-catalyzed carbonylation of alkyl bromides/tosylates to afford dialkyl ketones. The reaction shows broad substrate scope and good functional group tolerance.
- Sun, Yuren,Su, Lei,Tong, Weiqi,Yao, Ken,Gong, Hegui
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supporting information
p. 1762 - 1766
(2021/08/13)
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- C-H Alkylation of Aldehydes by Merging TBADT Hydrogen Atom Transfer with Nickel Catalysis
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Catalyst controlled site-selective C-H functionalization is a challenging but powerful tool in organic synthesis. Polarity-matched and sterically controlled hydrogen atom transfer (HAT) provides an excellent opportunity for site-selective functionalization. As such, the dual Ni/photoredox system was successfully employed to generate acyl radicals from aldehydes via selective formyl C-H activation and subsequently cross-coupled to generate ketones, a ubiquitous structural motif present in the vast majority of natural and bioactive molecules. However, only a handful of examples that are constrained to the use of aryl halides are developed. Given the wide availability of amines, we developed a cross-coupling reaction via C-N bond cleavage using the economic nickel and TBADT catalyst for the first time. A range of alkyl and aryl aldehydes were cross-coupled with benzylic and allylic pyridinium salts to afford ketones with a broad spectrum of functional group tolerance. High regioselectivity toward formyl C-H bonds even in the presence of α-methylene carbonyl or α-amino/oxy methylene was obtained.
- Murugesan, Vetrivelan,Ganguly, Anirban,Karthika, Ardra,Rasappan, Ramesh
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p. 5389 - 5393
(2021/07/21)
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- Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
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An unprecedented C═C double bond cleavage of cyclopropenone and dioxygen activation by multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fully substituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
- Yao, Liangliang,Hu, Qiong,Bao, Li,Zhu, Wenjing,Hu, Yimin
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supporting information
p. 4971 - 4975
(2021/06/30)
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- Iron-Catalyzed One-Step Synthesis of Isothiazolone/1,2-Selenazolone Derivatives via [3+1+1] Annulation of Cyclopropenones, Anilines, and Elemental Chalcogens
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Described herein is the one-step synthesis of isothiazolone/1,2-selenazolone derivatives via [3+1+1] cycloaddition of cyclopropenone derivatives, anilines, and elemental chalcogens. The cascade reaction involves the C?S, C?N, and N?S bond formation along with the cleavage of C?C bond. Both anilines and cyclopropenones are tolerated and give the corresponding products in 28–73% yields. (Figure presented.).
- Wang, Hongchen,Yan, Rulong
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supporting information
(2021/12/22)
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- Cascade Ring-Opening Dual Halogenation of Cyclopropenones with Saturated Oxygen Heterocycles
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Represented is a CuX2- or I2-promoted ring-opening dual halogenation of cyclopropenones with saturated oxygen heterocycles, providing an efficient method for the synthesis of 3-haloacrylates. The ring-opening reaction enables the construction of two C–X (X = Cl, Br, or I) bonds and a C–O bond as well as the cleavage of two C–O bonds and a C–C bond in a single step. This protocol is highly atom economical, has an excellent substrate scope, and exhibits the ability for gram-scale reaction.
- Gao, Wen-Xia,Huang, Xiao-Bo,Liu, Miao-Chang,Miao, Wei-Hang,Wu, Hua-Yue,Zhou, Yun-Bing
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supporting information
p. 9425 - 9430
(2021/12/14)
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- Sulfonium ion-promoted traceless Schmidt reaction of alkyl azides
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Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction through 1,2-migration of C-H and C-C bonds was accessible to the one-pot substitution reaction.
- Ardiansah, Bayu,Kakiuchi, Kiyomi,Morimoto, Tsumoru,Tanimoto, Hiroki,Tomohiro, Takenori
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supporting information
p. 8738 - 8741
(2021/09/08)
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- Cyclopentadienopyrazine organic compound and application thereof
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The invention relates to a cyclopentadienopyrazine organic compound and application thereof. The organic compound has a structure as shown in a general formula (1). The organic compound according to the present invention has excellent hole transport properties and stability, can be used as a hole injection layer material in an organic electroluminescent element, and can also be doped in a hole injection layer or a hole transport layer as a doping agent, so that a device can be driven at a low voltage, the electroluminescent efficiency can be improved, and the service life of the device can beprolonged.
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Paragraph 0229-0232
(2021/03/30)
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- Tetraaryl Cyclopentadienones: Experimental and Theoretical Insights into Negative Solvatochromism and Electrochemistry
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The synthesis of a series of tetraaryl cyclopentadienones comprising different substitution patterns is reported. Their photophysical and electrochemical properties are investigated by UV/Vis spectroscopy and cyclic voltammetry as well as by supporting quantum chemical simulations and reveal a distinct effect of substituents on the redox behavior of the molecules as well as the absorption properties of this class of compounds. While electrochemical data display a shift in reduction potential of up to 200 mV between the differently substituted cyclopentadienones, their photophysical investigations in differently polar solvents suggest a negative solvatochromic effect, although protic solvents induce a bathochromic shift. Crystal structure analyses of some derivatives confirm similarity with related cyclopentadienones while providing insight into intermolecular C–H···O and C–H···π interactions in the solid state.
- Meitinger, Nicolas,Mengele, Alexander K.,Witas, Kamil,Kupfer, Stephan,Rau, Sven,Nauroozi, Djawed
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p. 6555 - 6562
(2020/10/02)
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- N-heterocyclic carbene-palladium-imine complex catalyzed α-arylation of ketones with aryl and heteroaryl chlorides under air atmosphere
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A new structure of saturated ring skeleton monoligated NHC-Pd-Imine complex was easily synthesized and unambiguously confirmed by X-ray single crystal diffraction. It was found to be an efficient and air-stable catalyst for the α-arylation of ketones. The reaction could be operated in air without any negative effect. Non-activated aryl and heteroaryl chlorides have been successfully applied in the reaction with only 0.5 mol% catalyst loadings under air atmosphere. Excellent to good product yields were afforded.
- Lu, Hui-Yang,Shen, An,Li, Yong-Qing,Hu, Yu-Cai,Ni, Chen,Cao, Yu-Cai
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supporting information
(2020/06/24)
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- Rh(III)-Catalyzed [3 + 3] Annulation Reaction of Cyclopropenones and Sulfoxonium Ylides toward Trisubstituted 2-Pyrones
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A new Rh(III)-catalyzed [3 + 3] annulation reaction between cyclopropenones and β-ketosulfoxonium ylides has been reported, enabling metal carbene insertion to access a wide range of trisubstituted 2-pyrones with moderate to excellent yields via C-C single-bond cleavage, in which sulfoxonium ylides serve as potential safe precursors of metal carbenes. This reaction occurred under redox-neutral conditions with a broad substrate scope.
- Zhou, Peng,Yang, Wei-Tao,Rahman, Anis Ur,Li, Guigen,Jiang, Bo
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p. 360 - 366
(2019/11/14)
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- Ketone Synthesis from Benzyldiboronates and Esters: Leveraging α-Boryl Carbanions for Carbon-Carbon Bond Formation
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An alkoxide-promoted method for the synthesis of ketones from readily available esters and benzyldiboronates is described. The synthetic method is compatible with a host of sterically differentiated alkyl groups, alkenes, acidic protons α to carbonyl groups, tertiary amides, and aryl rings having common organic functional groups. With esters bearing α-stereocenters, high enantiomeric excess was maintained during ketone formation, establishing minimal competing racemization by deprotonation. Monitoring the reaction between benzyldiboronate and LiOtBu in THF at 23 °C allowed for the identification of products arising from deborylation to form an α-boryl carbanion, deprotonation, and alkoxide addition to form an "-ate" complex. Addition of 4-trifluoromethylbenzoate to this mixture established the α-boryl carbanion as the intermediate responsible for C-C bond formation and ultimately ketone synthesis. Elucidation of the role of this intermediate leveraged additional bond-forming chemistry and enabled the one-pot synthesis of ketones with α-halogen atoms and quaternary centers with four-different carbon substituents.
- Lee, Boran,Chirik, Paul J.
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supporting information
p. 2429 - 2437
(2020/03/03)
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- From Alkyl Halides to Ketones: Nickel-Catalyzed Reductive Carbonylation Utilizing Ethyl Chloroformate as the Carbonyl Source
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Ketones are an important class of molecules in synthetic and medicinal chemistry. Rapid and modular synthesis of ketones remains in high demand. Described here is a nickel-catalyzed three-component reductive carbonylation method for the synthesis of dialkyl ketones. A wide range of both symmetric and asymmetric dialkyl ketones can be accessed from alkyl halides and a safe CO source, ethyl chloroformate. The approach offers complementary substrate scope to existing carbonylation methods while avoiding the use of either toxic CO or metal carbonyl reagents.
- Shi, Renyi,Hu, Xile
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supporting information
p. 7454 - 7458
(2019/04/30)
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- Carbonylative Coupling of Alkyl Zinc Reagents with Benzyl Bromides Catalyzed by a Nickel/NN2 Pincer Ligand Complex
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An efficient catalytic protocol for the three-component assembly of benzyl bromides, carbon monoxide, and alkyl zinc reagents to give benzyl alkyl ketones is described, and represents the first nickel-catalyzed carbonylative coupling of two sp3-carbon fragments. The method, which relies on the application of nickel complexed with an NN2-type pincer ligand and a controlled release of CO gas from a solid precursor, works well with a range of benzylic bromides. Mechanistic studies suggest the intermediacy of carbon-centered radicals.
- Andersen, Thomas L.,Donslund, Aske S.,Neumann, Karoline T.,Skrydstrup, Troels
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supporting information
p. 800 - 804
(2017/12/26)
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- Organocatalytic Regiodivergent C?C Bond Cleavage of Cyclopropenones: A Highly Efficient Cascade Approach to Enantiopure Heterocyclic Frameworks
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Here a highly efficient cascade approach is reported that combines a cycloaddition reaction with a regioselective strain-release process to afford diverse heterocyclic frameworks through bifunctional catalysis. The cooperation of hydrogen-bonding network activation and a regiodivergent strain-assisted effect is the key to promoting this complex chemical transformation, leading to the generation of two different ring systems in high yields with excellent stereoselectivities. The reaction proceeded by a mechanism involving a “spring-loaded” intermediate with switchable C?C bond cleavages achieved by controllable ring-strain release. This reaction was also amenable to gram scale synthesis with only 0.1 mol % catalyst loading.
- Cao, Jian,Fang, Ran,Liu, Jin-Yu,Lu, Hong,Luo, Yong-Chun,Xu, Peng-Fei
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supporting information
p. 18863 - 18867
(2018/11/23)
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- Iron-catalyzed urea synthesis: Dehydrogenative coupling of methanol and amines
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Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas via the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H2 as the sole byproduct. Mechanistic studies indicate a stepwise pathway beginning with methanol dehydrogenation to give formaldehyde, which is trapped by amine to afford a formamide. The formamide is then dehydrogenated to produce a transient isocyanate, which reacts with another equivalent of amine to form a urea. These mechanistic insights enabled the development of an iron-catalyzed method for the synthesis of unsymmetric ureas from amides and amines.
- Lane, Elizabeth M.,Hazari, Nilay,Bernskoetter, Wesley H.
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p. 4003 - 4008
(2018/05/04)
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- Organic electroluminescence material with electron transmission effect and organic light emitting device thereof
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The invention provides an organic electroluminescence material with an electron transmission effect and an organic light emitting device thereof, and belongs to the technical field of organic photoelectrical materials, which solves the technical problems of low light emitting efficiency, higher driving voltage, shorter service life and the like of the organic photoelectrical material in the prior art. Compared with the prior art, the organic electroluminescence material with the electron transmission effect and the organic light emitting device thereof have the advantages that the minimum driving voltage is 3.9V, the maximum light emitting efficiency is 21.4cd/A, and an excellent OLED (organic light emitting diode) material is provided.
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Paragraph 0032; 0034
(2017/10/22)
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- Nitrite-containing resin as an efficient and recyclable catalyst for aerobic oxidation of oximes to carbonyl compounds
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Using novel nitrite-containing resin as an NO source and Amberlyst-15 as cocatalyst, we developed aerobic oxidation of oximes to corresponding carbonyl compounds with molecular oxygen as a clean oxidant reagent. It was distinguished from the previous related reports, and the experimental results indicated that additional water obviously decreased the yield. This process provides a better choice for oxidative deoximation with many advantages, such as high yield, simple procedure, high catalytic performance, and recyclable catalyst.
- Guo, Shu,Zeng, Renyou,Li, Caiye
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supporting information
p. 1446 - 1453
(2016/09/14)
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- PROCESS FOR HYDROGENATION OF OLEFINIC OR ACETYLENIC BONDS
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The present invention relates to a process for hydrogenation of olefinic or acetylenic bonds. Further, the present invention relates to a process for selective hydrogenation of olefinic or acetylenic bonds and/including triglycerides using modified metal supported on solid acidic metal oxide catalyst and the process for the preparation thereof. The present invention provides a process for hydrogenation of olefinic or acetylenic bonds using metal supported on solid acid metal oxide based catalyst, at moderate conditions. The present invention also relates to the preparation of metal supported on solid acid metal oxide based catalyst for hydrogenation reactions under mild conditions.
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Paragraph 0071
(2015/09/23)
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- Chloral hydrate as a water carrier for the efficient deprotection of acetals, dithioacetals, and tetrahydropyranyl ethers in organic solvents
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The efficient deprotection of several acetals, dithioacetals, and tetrahydropyranyl (THP) ethers under ambient conditions, using chloral hydrate in hexane, is described. Excellent yields were realized for a wide range of both aliphatic and aromatic substrates. The method is characterized by mild conditions (room temperatures or below), simple workup, and the ready availability of chloral hydrate. High chemoselectivity was also observed in the deprotection, acetonides, esters, and amides being unaffected under the reaction conditions. Products were generally purified chromatographically and identified spectrally. These results constitute a novel addition to current methodology involving a widely employed deprotection tactic in organic synthesis. It seems likely that the mechanism of the reaction involves adsorption of the substrate on the surface of the sparingly soluble chloral hydrate.
- Chandrasekhar, Sosale,Shrinidhi, Annadka
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p. 1904 - 1913
(2014/07/07)
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- BIO-ORTHOGONAL DRUG ACTIVATION
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Disclosed is a kit for the administration and activation of a Prodrug. The kit comprises a Masking Moiety linked, directly or indirectly, to a Trigger moiety, which in turn is linked to a Drug, and an Activator for the Trigger moiety. The Trigger moiety comprises a dienophile and the Activator comprises a diene, whereby the dienophile is an eight-membered non- aromatic cyclic alkenylene group, preferably a cyclooctene group, and more preferably a trans-cyclooctene group. The Trigger and the Activator undergo a fast, bio-orthogonal reaction resulting in the release of the Masking Moiety, and activation of the drug.
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Page/Page column 89-90; 92
(2014/06/11)
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- CHEMICALLY CLEAVABLE GROUP
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Disclosed is the use of the reactive components of the inverse electron-demand Diels Alder reaction for chemical masking and unmasking in vitro. This can be applied in complex chemical reactions and, particularly in the synthesis of biomolecules, e.g. on solid supports. The reactice components are a dienophile, particularly a trans-cyclooctene, and a diene, particularly a tetrazine.
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- CHANNEL PROTEIN ACTIVATABLE LIPOSOMES
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Disclosed is a liposome, comprising a lipid bilayer enclosing a cavity, wherein the bilayer comprises a channel protein releasably linked to an eight-membered non-aromatic cyclic alkenylene group, preferably a cyclooctene group, and more preferably a trans-cyclooctene group. The liposomes are used in a kit comprising the liposome, the liposomal membrane of which comprises a channel protein linked to a Trigger, and an Activator for the Trigger, wherein the Trigger comprises the eight- membered non-aromatic cyclic alkenylene group, and the Activator comprises a diene.
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Page/Page column 114; 116
(2014/06/11)
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- ACTIVATABLE LIPOSOMES
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Disclosed are reactive liposome, comprising a lipid bilayer enclosing a cavity, wherein the bilayer comprises a linkage to an eight-membered non-aromatic cyclic alkenylene group, preferably a cyclooctene group, and more preferably a trans-cyclooctene group. The liposomes are use in a kit comprising the liposome linked, directly or indirectly, to a Trigger, and an Activator for the Trigger, wherein the Trigger comprises an eight-membered non-aromatic cyclic alkenylene group, and the Activator comprises a diene.
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Page/Page column 131; 133
(2014/06/11)
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- Gram-scale ketone synthesis by direct reductive coupling of alkyl iodides with acid chlorides
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Alkyl aryl ketones were prepared on a gram scale by the nickel-catalyzed reductive coupling of alkyl iodides with aroyl chlorides. When scaled up 30-fold, this reaction shows a comparable coupling efficiency to the previously reported reaction performed under small-scale conditions. The mild and convenient reaction conditions show excellent tolerance to a range of functional groups and provide the ketones in good to excellent yields. Georg Thieme Verlag Stuttgart. New York.
- Lu, Wenbin,Liang, Zhuye,Zhang, Yuwei,Wu, Fan,Qian, Qun,Gong, Hegui
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p. 2234 - 2240
(2013/09/02)
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- Ketone formation via mild Nickel-catalyzed reductive coupling of alkyl halides with aryl acid chlorides
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The present work highlights unprecedented Ni-catalyzed reductive coupling of unactivated alkyl iodides with aryl acid chlorides to efficiently generate alkyl aryl ketones under mild conditions.
- Wu, Fan,Lu, Wenbin,Qian, Qun,Ren, Qinghua,Gong, Hegui
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supporting information; experimental part
p. 3044 - 3047
(2012/08/07)
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- Palladium-catalyzed carbonylative negishi-type coupling of aryl iodides with benzyl chlorides
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Do the competition: The synthesis of 1,2-diarylethanones has been accomplished using the palladium-catalyzed coupling of aryl iodides and CO/benzyl chlorides or benzoyl chlorides. These reactions proceed smoothly in the presence of zinc powder to afford the products in moderate to excellent yields.
- Wu, Xiao-Feng,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 40 - 44
(2012/03/11)
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- Gold-catalysed activation of epoxides: Application in the synthesis of bicyclic ketals
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Gold-catalysed generation of diol equivalents from epoxides and their intramolecular reaction with Ca≡C bonds to generate bicyclic ketals is presented. This reaction essentially involves the formation of an acetonide, which subsequently cyclises on the alkyne intramolecularly under gold catalysis conditions. This method could be extended to make optically pure bicyclic ketals. Deuterium incorporation experiments were carried out to ascertain the mechanism of the reaction. Sequential activation of epoxide and alkyne moieties by a gold catalyst in acetone as solvent has been achieved. This strategyhas been employed to synthesise bicyclic ketals from epoxy alkynes. Copyright
- Balamurugan, Rengarajan,Kothapalli, Raveendra Babu,Thota, Ganesh Kumar
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scheme or table
p. 1557 - 1569
(2011/04/25)
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- Catalytic Decarboxylative Cross-Ketonisation of Aryl- and Alkylcarboxylic Acids using Magnetite Nanoparticles
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In the presence of catalytic amounts of magnetite nanopowder, mixtures of aromatic and aliphatic carboxylic acids are converted selectively into the corresponding aryl alkyl ketones. As by-products, only carbon dioxide and water are released. This catalytic cross-ketonisation allows the regioselective acylation of aromatic systems and, thus, represents a sustainable alternative to Friedel-Crafts acylations.
- Goossen, Lukas J.,Mamone, Patrizia,Oppel, Christoph
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supporting information; experimental part
p. 57 - 63
(2011/03/22)
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- Polymer-supported α-aminonitriles: Alkylation reactions and carbonyl compound cleavage
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A polystyrene-supported α-aminonitrile has been prepared and its successive mono- and dialkylations achieved. Complementary procedures allow cleavage of the alkylated moities in either carbonyl or acetal form. Georg Thieme Verlag Stuttgart - New York.
- Beaufort-Droal, Virginie,Pereira, Elisabeth,Vergne, Fabrice,Aitken, David J.
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experimental part
p. 2913 - 2917
(2011/02/25)
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- Reactivity of the 4-amino-5H-1,2-oxathiole-2,2-dioxide heterocyclic system: A combined experimental and theoretical study
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The reactivity of the 4-amino-5H-1,2-oxathiole-2,2-dioxide (or β-amino-γ-sultone) heterocyclic system has scarcely been studied. Here we describe the reactivity of this system towards electrophiles and amines on readily available model substrates differently substituted at the C-5 position. A variety of C-electrophiles, carbonyl electrophiles (such as acyl chlorides, isocyanates, or aldehydes) and halogen or nitrogen electrophiles have been explored. Both the C-3 and 4-amino positions of the β-amino-γ- sultone system are able to undergo electrophilic reactions, and the reaction products depend on the electrophile used and on the reaction conditions. On the other hand, nucleophilic attack of amines occurs at the C-4 position of the β-amino-γ-sultone system only in spiranic substrates bearing alicyclic substituents at the C-5 position. A comparative computational study between spiranic and non-spiranic substrates suggests that conformational changes, undergone on intermediate compounds, account for the observed reactivity differences. Moreover, these conformational changes seem to bring about an increase of electron density on the N-4 and C-3 atoms of the enaminic system, and a possible enhancement in the reactivity of spiranic substrates towards electrophiles in the presence of amines. Experimental data consistent with this predicted enhanced reactivity is also presented.
- De Castro, Sonia,Teresa Peromingo,Lozano, Angel E.,Camarasa, Maria-Jose,Velazquez, Sonsoles
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body text
p. 9620 - 9632
(2009/10/01)
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- Nitric oxide-releasing molecules
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This invention relates to compositions comprising carbon-based diazeniumdiolates that release nitric oxide (NO). The carbon-based diazeniumdiolated molecules release NO spontaneously under physiological conditions without subsequent nitrosamine formation. The present invention also relates to methods of preparing the carbon-based diazeniumdiolated molecules, compositions comprising such molecules, methods of using such compositions, and devices employing such molecule compositions.
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Page/Page column 8
(2008/06/13)
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- Hammett analysis of photodecarbonylation in crystalline 1,3-diarylacetones
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(Chemical Equation Presented) The relative quantum yields and chemical efficiencies of crystalline p,p′-disubstituted 1,3-diphenyl-2-propanones with 4-MeO, 4-Me, 4-F, 4-CF3, and 3,4-diMeO groups were determined by parallel irradiation of polycrystalline samples. Variations in quantum yields that span a factor of 4 are analyzed in terms of the effects of substituents on the stability of the benzylic radical. All solid-state reactions proceeded with 100% chemoselectivity and in >95% chemical yield.
- Resendiz, Marino J. E.,Garcia-Garibay, Miguel A.
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p. 371 - 374
(2007/10/03)
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- Pd(0)-Catalyzed Conjugate Addition of Benzylzinc Chlorides to α,β-Enones in An Atmosphere of Carbon Monoxide: Preparation of 1,4-Diketones
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Pd(0)-catalyzed conjugate addition of benzylzine chloride to methyl vinyl ketone in the presence of chlorotrimethylsilane and lithium chloride in an atmosphere of carbon monoxide at room temperature afforded 1-phenyl-2,5-hexanedione monosilyl enol ether. In this catalytic carbonylation, four components are connected in one reaction. Successive acidic workup generated a variety of 1,4-diketones from substituted benzylzine chlorides or related compounds and α,β-enones. Some products were converted to cyclopentenones or five-membered heterocyclic compounds containing an N, O, or S atom.
- Yuguchi, Motoki,Tokuda, Masao,Orito, Kazuhiko
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p. 908 - 914
(2007/10/03)
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- Remarkable reactivity of pyridinium chlorochromate adsorbed on neutral alumina under solvent-free conditions
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Pyridinium chlorochromate adsorbed on neutral alumina (PCC-Al2O3) under solvent-free conditions has been found to oxidize primary aliphatic alcohols to alkyl alkanoates whereas primary benzylic and primary allylic alcohols produce the corresponding aldehydes. Secondary aliphatic and aromatic alcohols produce ketones without isomerization and polymerization of double bonds, overoxidation and other side-reactions.
- Bhar, Sanjay,Chaudhuri, Subrata Kumar
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p. 3493 - 3498
(2007/10/03)
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- Rotamase enzyme activity inhibitors
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This invention relates to methods of using neurotrophic compounds having an affinity for FKBP-type immunophilins to stimulate or promote neuronal growth or regeneration and to prevent neuronal degeneration.
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- Rotamase enzyme activity inhibitors
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This invention relates to methods of using neurotrophic compounds having an affinity for FKBP-type immunophilins to stimulate or promote neuronal growth or regeneration and to prevent neuronal degeneration.
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- 4-hydroxyisothiazole compounds
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The present invention relates to the use of 4-hydroxyisothiazole compounds as antimicrobially active substances, certain new 4-hydroxyisothiazole compounds and a process for their preparation.
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- Small molecule inhibitors of rotamase enzyme activity
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This invention relates to neurotrophic compounds having an affinity for FKBP-type immunophilins, their preparation and use as inhibitors of the enzyme activity associated with immunophilin proteins, and particularly inhibitors of peptidyl-prolyl isomerase or rotamase enzyme activity.
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- Deprotection of ketone dimethylhydrazones using lipases
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Deprotection of ketone dimethylhydrazone compounds with porcine pancreatic lipase (PPL) as a biocatalyst is described. (C) 2000 Elsevier Science Ltd.
- Mino, Takashi,Matsuda, Terumi,Hiramatsu, Dai,Yamashita, Masakazu
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p. 1461 - 1463
(2007/10/03)
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