- Nickel-Catalyzed Multicomponent Coupling: Synthesis of α-Chiral Ketones by Reductive Hydrocarbonylation of Alkenes
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A nickel-catalyzed, multicomponent regio- and enantioselective coupling via sequential hydroformylation and carbonylation from readily available starting materials has been developed. This modular multicomponent hydrofunctionalization strategy enables the straightforward reductive hydrocarbonylation of a broad range of unactivated alkenes to produce a wide variety of unsymmetrical dialkyl ketones bearing a functionalized α-stereocenter, including enantioenriched chiral α-aryl ketones and α-amino ketones. It uses chiral bisoxazoline as a ligand, silane as a reductant, chloroformate as a safe CO source, and a racemic secondary benzyl chloride or an N-hydroxyphthalimide (NHP) ester of a protected α-amino acid as the alkylation reagent. The benign nature of this process renders this method suitable for late-stage functionalization of complex molecules.
- Chen, Jian,Zhu, Shaolin
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supporting information
p. 14089 - 14096
(2021/09/13)
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- Ferric chloride–catalyzed deoxygenative chlorination of carbonyl compounds: A comparison of chlorodimethylsilane and dichloromethylsilane system
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Deoxygenative chlorination of carbonyl compounds using the HMe2SiCl/FeCl3/EtOAc and HMeSiCl2/FeCl3/EtOAc systems has been systemically investigated. The HMe2SiCl-FeCl3 system showed the advantages of good substrate applicability, mild reaction conditions, simple operation, low cost, and easy availability of raw materials. Also, it provided a simple and efficient synthesis route for carbonyl deoxychlorination via a one-pot method. Using the HMeSiCl2/FeCl3/EtOAc system, the β-methylchalcone derivative could be obtained in good yields in addition to obtaining the chlorinated compound. Finally, two plausible reaction routes were proposed to describe the formation of the chlorinated compound and the β-methylchalcone derivative.
- Xing, Bing-Han,Zhao, Xuan-Xuan,Qin, Yu-Jun,Zhang, Pu,Guo, Zhi-Xin
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p. 667 - 675
(2020/05/22)
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- Manganese-salen catalyzed oxidative benzylic chlorination
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Abstract: Metalloporphyrins are well-known to serve as the model for mimicking reactivities exhibited by cytochrome P450 hydroxylase. Recent developments on selective C–H halogenation using Mn-porphyrins provided the way for understanding the reactivity as well as mechanism of different halogenase enzymes. In this report, we demonstrated a method for benzylic C–H chlorination using easily prepared Mn(salen) complex as the catalyst, which shows a complementary reactivity of Mn-porphyrins. Here, NaOCl has been used as a chlorinating source as well as the oxidant. Efforts towards understanding the mechanism suggested the formation of the high-valent Mn(V)=O species which is believed to be the key intermediate to conduct this transformation. Graphical abstract: SYNOPSIS Mn(salen)-catalyzed selective benzylic chlorination protocol has been developed using aqueous NaOCl solution. Reactions proceeded efficiently at room temperature and displayed good functional group tolerance. The mechanistic investigation demonstrated that Mn (V) = O species is likely to be the key intermediate which is responsible to generate benzylic radical. EPR and ESI-MS studies confirmed the in situ formation of Mn(IV)-species.[Figure not available: see fulltext.].
- Sasmal, Sheuli,Rana, Sujoy,Lahiri, Goutam Kumar,Maiti, Debabrata
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- Silver-Catalyzed C(sp3)-H Chlorination
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A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp3)-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.
- Ozawa, Jun,Kanai, Motomu
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supporting information
p. 1430 - 1433
(2017/03/23)
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- Iron catalyzed halogenation of benzylic aldehydes and ketones
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A simple and efficient iron-catalyzed method for chlorination of aromatic carbonyl compounds is reported. By using 4-10 mol% Fe(iii) oxo acetate catalyst, prepared by solid state atmospheric oxidation of Fe(ii) acetate, in combination with triethylsilane and chlorotrimethylsilane, hydrosilylation of benzylic carbonyl compounds with subsequent chlorination is achieved within a few hours at room temperature. This new method is mild and rapid compared to the conventional two step approach involving reduction and chlorination reactions in separate stages. Development of synthetic methodology is also supplemented here by kinetic investigation of the reaction mechanism, which supports the tentative mechanisms suggested previously for similar reactions. This journal is
- Savela, Risto,W?rn?, Johan,Murzin, Dmitry Yu.,Leino, Reko
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p. 2406 - 2417
(2015/04/14)
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- A procedure for Appel halogenations and dehydrations using a polystyrene supported phosphine oxide
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The conversion of a commercially available polystyrene supported phosphine oxide into synthetically useful polymeric halophosphonium salts using oxalyl chloride/bromide takes place at room temperature in 5 min and generates only CO and CO2 as by-products. The polymeric halophosphonium salts so obtained are useful reagents for Appel halogenations and other dehydrative coupling reactions. This gives rise to a simple three-step synthesis cycle for Appel and related reactions using a commercially available polymeric phosphine oxide with very simple purification and no phosphorus waste.
- Tang, Xiaoping,An, Jie,Denton, Ross M.
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p. 799 - 802
(2014/02/14)
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- Nickel-catalyzed asymmetric reductive cross-coupling between vinyl and benzyl electrophiles
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A Ni-catalyzed asymmetric reductive cross-coupling between vinyl bromides and benzyl chlorides has been developed. This method provides direct access to enantioenriched products bearing aryl-substituted tertiary allylic stereogenic centers from simple, stable starting materials. A broad substrate scope is achieved under mild reaction conditions that preclude the pregeneration of organometallic reagents and the regioselectivity issues commonly associated with asymmetric allylic arylation.
- Cherney, Alan H.,Reisman, Sarah E.
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supporting information
p. 14365 - 14368
(2014/12/11)
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- DMSO-catalyzed chlorination of alcohols using N-phenylbenzimidoyl chloride
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N-phenylbenzimidoyl chloride has been demonstrated as an efficient chlorination reagent catalyzed by dimethyl sulfoxide (DMSO) in conversion of alcohols to corresponding chlorides. The reaction conditions were mild, and most of the substrates gave satisfactory yields. The configuration inversion of the chlorination was proved using optically active phenyl alcohols. The amount of DMSO can be as low as 0.001 eq without reducing the efficiency of the chlorination. A plausible mechanism for the reaction was proposed and proved by experiments. The reaction is stereoselective and potentially chemoselective among primary benzyl alcohols, secondary benzyl alcohols, and unactivated aliphatic alcohols.
- Wang, Qiang,Xu, Jian,Xu, Zhou-Qing,Yan, Ji-Dan
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p. 2071 - 2076
(2013/06/05)
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- Catalytic asymmetric reductive acyl cross-coupling: Synthesis of enantioenriched acyclic α,α-disubstituted ketones
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The first enantioselective Ni-catalyzed reductive acyl cross-coupling has been developed. Treatment of acid chlorides and racemic secondary benzyl chlorides with a NiII/bis(oxazoline) catalyst in the presence of Mn0 as a stoichiometric reductant generates acyclic α,α-disubstituted ketones in good yields and high enantioselectivity without requiring stoichiometric chiral auxiliaries or pregeneration of organometallic reagents. The mild, base-free reaction conditions are tolerant of a variety of functional groups on both coupling partners.
- Cherney, Alan H.,Kadunce, Nathaniel T.,Reisman, Sarah E.
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supporting information
p. 7442 - 7445
(2013/06/27)
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- NOVEL COMPOUNDS USEFUL FOR THE TREATMENT OF DEGENERATIVE AND INFLAMMATORY DISEASES
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Novel [1,2,4]triazolo[1,5-a]pyridine compounds are disclosed that have a Formula represented by the Formula (I). These compounds may be prepared as a pharmaceutical composition, and may be used for the prevention and treatment of a variety of conditions in mammals including humans, including by way of non-limiting example, diseases involving cartilage degradation, bone and/or joint degradation, for example osteoarthritis; and/or conditions involving inflammation or immune responses, such as Crohn's disease, rheumatoid arthritis, psoriasis, allergic airways disease (e.g. asthma, rhinitis), juvenile idiopathic arthritis, colitis, inflammatory bowel diseases, endotoxin-driven disease states (e.g. complications after bypass surgery or chronic endotox in states contributing to e.g. chronic cardiac failure), diseases involving impairment of cartilage turnover (e.g. diseases involving the anabolic stimulation of chondrocytes), congenital cartilage malformations, diseases associated with hypersecretion of IL6 and transplantation rejection (e.g. organ transplant rejection) and proliferative diseases.
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Page/Page column 67
(2010/04/03)
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- [1, 2, 4] TRIAZOLO [1, 5-A] PYRIDINES AS JAK INHIBITORS
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Novel [1,2,4]triazolo[1,5-a]pyridine compounds are disclosed that have a Formula represented by the following: (I). The compounds may be prepared as pharmaceutical compositions, and may be used for the prevention and treatment of a variety of conditions in mammals including humans, including by way of non-limiting example, joint disease, inflammation, and others.
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Page/Page column 102
(2010/04/03)
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- COMPOUNDS FOR THE TREATMENT OF INFLAMMATORY DISORDERS
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This invention relates to compounds of the Formula (I): (Chemical formula should be inserted here as it appears on abstract in paper form) (I) or a pharmaceutically acceptable salt, solvate or isomer thereof, which can be useful for the treatment of diseases or conditions mediated by MMPs, ADAMs, TACE, aggrecanase, TNF- or combinations thereof.
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Page/Page column 164-165
(2010/06/11)
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- PYRIMIDINONE DERIVATIVES AND METHODS OF USE THEREOF
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The present invention relates to Pyrimidinone Derivatives, compositions comprising a Pyrimidinone Derivative, and methods of using the Pyrimidinone Derivatives for treating or preventing obesity, diabetes, a metabolic disease, a cardiovascular disease or a disorder related to the activity of GPR119 in a patient.
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Page/Page column 152
(2008/12/08)
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