- A facile, microwave-assisted, palladium-catalyzed arylation of acetone
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We report an expedient method for the heteroarylation of acetone under tin-free conditions. The coupling is performed using the commercially available enol silane of acetone (2-trimethylsilyloxypropene) and a corresponding aryl bromide, chloride or triflate under microwave-assisted conditions, with tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) or palladium acetate (Pd(OAc)2) and 2-(2′,6′-dimethoxybiphenyl)dicyclohexylphosphine (S-Phos) as the catalyst system.
- Chobanian, Harry R.,Liu, Ping,Chioda, Marc D.,Guo, Yan,Lin, Linus S.
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- COMPOUNDS AND COMPOSITIONS FOR TREATING CONDITIONS ASSOCIATED WITH STING ACTIVITY
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The present invention relates to chemical entities (for example, a pharmaceutically acceptable compound or salt, and / or a hydrate, and / or a co-crystal, and / or a combination of drug of the compound) which inhibit (for example, antagonize) the stimula
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Page/Page column 144-145
(2022/01/24)
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- Aryl C-F bond functionalization preparation method
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The invention relates to the technical field of organic compound synthesis, in particular to an aryl C-F bond functionalization preparation method. A fluorobenzene compound and a nucleophilic reagent react under the action of a composite catalyst, wherein the composite catalyst is formed by mixing a visible light catalyst and a metal catalyst. The photocatalyst is adopted, the reaction process is safe and controllable, and operation in the preparation and production process is simplified; a purple LED is used as a reaction energy source and is green and environment-friendly, the energy utilization rate is high, and conversion from light energy to chemical energy can be efficiently realized; in the reaction, a simple nucleophilic reagent is used for attacking free radical cation species generated under a visible light catalysis condition, so that a target product with an extremely wide range is efficiently and greenly prepared; the operation steps are simplified, and the reaction route is shortened; and moreover, the forward reaction rate is high, and the production efficiency is remarkably improved.
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Paragraph 0052; 0089-0093; 0099-0102
(2021/09/29)
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- Direct Synthesis of Propen-2-yl Sulfones through Cascade Reactions Using Calcium Carbide as an Alkyne Source
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A simple method for the construction of propen-2-yl sulfones through cascade reactions of calcium carbide with arylsulfonylhydrazones using copper as a mediator is described. The salient features of this protocol are the use of readily available and easy-to-handle alkyne source, broad substrate scope, open-air condition, and simple operation procedure.
- Gao, Lei,Liu, Zhenrong,Ma, Xiaolong,Li, Zheng
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supporting information
p. 5246 - 5250
(2020/07/04)
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- Nickel-Catalyzed Mono-Selective α-Arylation of Acetone with Aryl Chlorides and Phenol Derivatives
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The challenging nickel-catalyzed mono-α-arylation of acetone with aryl chlorides, pivalates, and carbamates has been achieved for the first time. A nickel/Josiphos-based catalytic system is shown to feature unique catalytic behavior, allowing the highly selective formation of the desired mono-α-arylated acetone. The developed methodology was applied to a variety of (hetero)aryl chlorides including biologically relevant derivatives. The methodology has been extended to the unprecedented coupling of acetone with phenol derivatives. Mechanistic studies allowed the isolation and characterization of key Ni0 and NiII catalytic intermediates. The Josiphos ligand is shown to play a key role in the stabilization of NiII intermediates to allow a Ni0/NiII catalytic pathway. Mechanistic understanding was then leveraged to improve the protocol using an air-stable NiII pre-catalyst.
- Amgoune, Abderrahmane,Derhamine, Sary Abou,Krachko, Tetiana,Monteiro, Nuno,Pilet, Guillaume,Schranck, Johannes,Tlili, Anis
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supporting information
p. 18948 - 18953
(2020/09/01)
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- UiO-66 microcrystals catalyzed direct arylation of enol acetates and heteroarenes with aryl diazonium salts in water
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UiO-66 is a classic Metal–organic framework (MOF) that constructed by zirconium cations and terephthalate with high chemical and thermal stability. Using pristine UiO-66 nanocrystals as the catalysts, the carbon–carbon bond formation based on denitrogenat
- Sun, Zhong-Hua,Chen, Wang,Qian, Bing-Bing,Wang, Liang,Yu, Binxun,Chen, Qun,He, Ming-Yang,Zhang, Zhi-Hui
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- Stereoselective Synthesis of 1-Arylpropan-2-amines from Allylbenzenes through a Wacker-Tsuji Oxidation-Biotransamination Sequential Process
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Herein, a sequential and selective chemoenzymatic approach is described involving the metal-catalysed Wacker-Tsuji oxidation of allylbenzenes followed by the amine transaminase-catalysed biotransamination of the resulting 1-arylpropan-2-ones. Thus, a series of nine optically active 1-arylpropan-2-amines were obtained with good to very high conversions (74–92%) and excellent selectivities (>99% enantiomeric excess) in aqueous medium. The Wacker-Tsuji reaction has been exhaustively optimised searching for compatible conditions with the biotransamination experiments, using palladium(II) complexes as catalysts and iron(III) salts as terminal oxidants in aqueous media. The compatibility of palladium/iron systems for the chemical oxidation with commercially available and made in house amine transaminases was analysed, finding ideal conditions for the development of a general and stereoselective cascade sequence. Depending on the selectivity displayed by selected amine transaminase, it was possible to produce both 1-arylpropan-2-amines enantiomers under mild reaction conditions, compounds that present therapeutic properties or can be employed as synthetic intermediates of chiral drugs from the amphetamine family. (Figure presented.).
- González-Martínez, Daniel,Gotor, Vicente,Gotor-Fernández, Vicente
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p. 2582 - 2593
(2019/05/15)
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- C-H arylation reactions through aniline activation catalysed by a PANI-g-C3N4-TiO2 composite under visible light in aqueous medium
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A PANI (polyaniline)-g-C3N4-TiO2 composite was prepared and found to be efficient for radical C-H arylation reactions. The arylation process involved coupling of in situ generated aryl diazonium salts from aniline with heteroarenes, enol acetates or benzoquinones under visible light in aqueous medium or pure water. A broad range of substrates survived the reaction conditions to provide the desired products in moderate to good yields. Scale-up (10 mmol) synthesis was also achieved. This semiconductor photocatalyst showed good photocatalytic performance and stability. Recycle studies showed that this composite could be readily recovered and a slight decrease in the catalytic activity was observed after ten consecutive runs.
- Wang, Liang,Shen, Jun,Yang, Sen,Liu, Wenjie,Chen, Qun,He, Mingyang
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supporting information
p. 1290 - 1296
(2018/03/26)
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- Anti-Markovnikov Oxidation of β-Alkyl Styrenes with H2O as the Terminal Oxidant
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Oxygenation of alkenes is one of the most straightforward routes for the construction of carbonyl compounds. Wacker oxidation provides a broadly useful strategy to convert the mineral oil into higher value-added carbonyl chemicals. However, the conventional Wacker chemistry remains problematic, such as the poor activity for internal alkenes, the lack of anti-Markovnikov regioselectivity, and the high cost and chemical waste resulted from noble metal catalysts and stoichiometric oxidant. Here, we describe an unprecedented dehydrogenative oxygenation of β-alkyl styrenes and their derivatives with water under external-oxidant-free conditions by utilizing the synergistic effect of photocatalysis and proton-reduction catalysis that can address these challenges. This dual catalytic system possesses the single anti-Markovnikov selectivity due to the property of the visible-light-induced alkene radical cation intermediate.
- Zhang, Guoting,Hu, Xia,Chiang, Chien-Wei,Yi, Hong,Pei, Pengkun,Singh, Atul K.,Lei, Aiwen
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supporting information
p. 12037 - 12040
(2016/09/28)
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- Preparation of a highly congested carbazoyl-derived p,n-type phosphine ligand for acetone monoarylations
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We report a newly developed carbazoyl-derived P,N-type phosphine ligand (L1) for the monoarylation of acetone with aryl chlorides. The proposed Pd(dba)2/L1 catalyst exhibited remarkable catalytic reactivity toward highly electron rich and sterically congested aryl chlorides, with catalyst loading as low as 0.1 mol % of Pd along with excellent chemoselectivity. A reaction rate study of the system using electronically diverse aryl chlorides determined the mechanisms regarding the rate-limiting steps in this reaction. The oxidative addition adduct of Pd-PhenCar-Phos with p-chlorotoluene showed the participation of N-Pd coordination in the metal complex. The isolated palladium complex C1 could be utilized as a precatalyst in the transformation and achieved performance comparable to that of the in situ generated palladium species.
- Fu, Wai Chung,Zhou, Zhongyuan,Kwong, Fuk Yee
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p. 1553 - 1558
(2016/06/09)
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- Expedient Access to 2,3-Dihydropyridines from Unsaturated Oximes by Rh(III)-Catalyzed C-H Activation
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α,β-Unsaturated oxime pivalates are proposed to undergo reversible C(sp2)-H insertion with cationic Rh(III) complexes to furnish five-membered metallacycles. In the presence of 1,1-disubstituted olefins, these species participate in irreversible migratory insertion to give, after reductive elimination, 2,3-dihydropyridine products in good yields. Catalytic hydrogenation can then be used to convert these molecules into piperidines, which are important structural components of numerous pharmaceuticals.
- Romanov-Michailidis, Fedor,Sedillo, Kassandra F.,Neely, Jamie M.,Rovis, Tomislav
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supporting information
p. 8892 - 8895
(2015/08/03)
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- Design of an Indolylphosphine Ligand for Reductive Elimination-Demanding Monoarylation of Acetone Using Aryl Chlorides
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The rational design of a phosphine ligand for the reductive elimination-demanding Pd-catalyzed mono-α-arylation of acetone is demonstrated and reported. The catalyst is tolerant of previously proven challenging electron-deficient aryl chlorides and provides excellent product yields with down to 0.1 mol % Pd. Preliminary investigations suggest that the rate-limiting step for the proposed system is the oxidative addition of aryl chlorides, in which it contradicts previous findings regarding the α-arylation of acetone with aryl halides.
- Fu, Wai Chung,So, Chau Ming,Chow, Wing Kin,Yuen, On Ying,Kwong, Fuk Yee
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supporting information
p. 4612 - 4615
(2015/09/28)
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- Palladium-catalyzed mono-α-arylation of acetone with aryl halides and tosylates
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We report the first example of selective Pd-catalyzed mono-α- arylation of acetone employing aryl chlorides, bromides, iodides, and tosylates. The use of appropriately designed P,N-ligands proved to be the key to controlling the reactivity and selectivity. The reaction affords good yields with substrates containing a range of functional groups at modest Pd loadings using Cs2CO3 as the base and employing acetone as both a reagent and the solvent.(Figure Presented)
- Hesp, Kevin D.,Lundgren, Rylan J.,Stradiotto, Mark
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supporting information; experimental part
p. 5194 - 5197
(2011/06/10)
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- Copper catalyzed arylation/C-C bond activation: An approach toward α-aryl ketones
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An efficient arylation/C-C activation process was discovered. -Diketones with aryl halides (aryl iodides and aryl bromides) could undergo reaction smoothly in the presence of Cu(I) or Cu(II) salts in DMSO using K3 PO4 3H2 O without ligands. The role of H2 O was unprecedented, which assisted the C-C activation. Various -aryl ketones could be efficiently synthesized by this novel method. In situ monitoring of the formation of KOAc and experimentation relating to "a classic diagnostic technique for the participation of radical anion intermediates" revealed the preliminary mechanistic information for the reaction. This method is simple, general, and practical which complemented the classic method for the rapid construction of C-C bonds to a carbonyl moiety.
- He, Chuan,Guo, Sheng,Huang, Li,Lei, Aiwen
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supporting information; scheme or table
p. 8273 - 8275
(2010/08/03)
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- A practical synthesis of α-aryl methyl ketones via a transition-metal-free Meerwein arylation
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We report herein a simple, scalable, transition-metal-free approach to the synthesis of α-aryl methyl ketones from diazonium tetrafluoroborate salts under mild conditions. This methodology uses easily accessible and nontoxic starting material and was applied to the multi-kilogram-scale preparation of 1-(3-bromo-4-methylphenyl)propan-2-one.
- Molinaro, Carmela,Mowat, Jeffrey,Gosselin, Francis,O'Shea, Paul D.,Marcoux, Jean-Francois,Angelaud, Remy,Davies, Ian W.
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p. 1856 - 1858
(2007/10/03)
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- Hydroboration with pyridine borane at room temperature
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Treatment of pyridine borane (Py·BH3) with iodine, bromine, or strong acids affords activated Py·BH2X complexes that are capable of hydroborating alkenes at room temperature. Evidence is presented for an unusual hydroboration mechanism involving leaving group displacement. In contrast to THF·BH3, hydroboration with Py·BH2I selectively affords the monoadducts. The crude hydroboration products are converted into synthetically useful potassium alkyltrifluoroborate salts upon treatment with methanolic KHF2. Copyright
- Clay, Julia M.,Vedejs, Edwin
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p. 5766 - 5767
(2007/10/03)
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- Evidence that the availability of an allylic hydrogen governs the regioselectivity of the Wacker oxidation
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The allylic hydrogen is found to have a dramatic effect on the regioselectivity of the Wacker oxidation, leading to the postulation that an agostic hydrogen or enyl (σ + π) complex helps to stabilise the key intermediate.
- Gaunt,Yu,Spencer
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p. 1844 - 1845
(2007/10/03)
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