- Chiral Phosphoric Acid Catalyzed Asymmetric Desymmetrization of para-Quinamines with Isocyanates: Access to Functionalized Imidazolidin-2-one Derivatives
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The development of enantioselective desymmetrization of para-quinamines with isocyanates catalyzed by chiral phosphoric acid is reported. The strategy provides concise access to functionalized imidazolidin-2-one derivatives in high yields and enantioselectivities under mild reaction conditions. Remarkably, this reaction could be performed on a gram scale using 5 mol % catalyst loading and the chiral imidazolidin-2-one derivatives could be easily transformed into valuable scaffolds without disturbing the enantiopurity, demonstrating the synthetic utility of this protocol.
- Hu, Kai-Wen,You, Xiao,Wang, Jin-Zheng,Wen, Xiaoan,Sun, Hongbin,Xu, Qing-Long,Lai, Zengwei
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supporting information
p. 7873 - 7877
(2021/10/20)
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- Transition-Metal-Free Regioselective One-Pot Synthesis of Aryl Sulfones from Sodium Sulfinates via Quinone Imine Ketal
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A novel, efficient, and regioselective transition-metal-free one-pot synthesis of aryl sulfones via the reactive quinone imine ketal intermediate is demonstrated using easily accessible bench-stable sulfinate salts. A broad range of functionality on p-ani
- Halder, Priyanka,Humne, Vivek T.,Mhaske, Santosh B.
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p. 1372 - 1378
(2019/01/30)
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- Lewis Base Promoted, Direct 1,4-Conjugate Addition to Quinone Imine Ketals: Efficient Access to Unsymmetrical Diaryl Sulfones
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An alternative approach with eco-friendliness and high efficiency for the preparation of unsymmetrical diaryl sulfones has been developed. The strategy takes advantage of the reaction of sulfonyl hydrazides with quinone imine ketals catalyzed by DABCO (triethylenediamine) in ethanol. This transformation proceeds via a Lewis base promoted, direct 1,4-conjugate addition/sulfonylation/alcohol elimination reaction sequence. The protocol provides an efficient approach to access an array of diverse unsymmetrical diaryl and heterodiaryl sulfones, aryl alkyl sulfones and aryl vinyl sulfones in good to excellent yields.
- Liu, Teng,Liu, Jianjun,Shen, Xianfu,Xu, Jianbin,Nian, Beifang,He, Ni,Zeng, Shunqun,Cheng, Feixiang
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p. 1365 - 1376
(2019/03/08)
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- Nitrogen-Bridged, Natural Product Like Octahydrobenzofurans and Octahydroindoles: Scope and Mechanism of Bridge-Forming Reductive Amination via Caged Heteroadamantanes
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The biological significance of sp3-rich synthetic scaffolds with natural product like features yet distinct global frameworks is being increasingly recognized in medicinal chemistry and biochemistry. Taking inspiration from the vast array of bi
- Wales, Steven. M.,Adcock, Holly V.,Lewis, William,Hamza, Daniel,Moody, Christopher J.
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supporting information
p. 4696 - 4704
(2018/09/14)
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- A chemical synthesis asymmetric structure dihalodiarylsulfone method (by machine translation)
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A chemical synthesis asymmetric structure dihalodiarylsulfone method, to substituted aniline compound 1 as a starting raw material, first on the aniline Ts (toluene sulfonyl) protection or Boc (tert-butoxy carbonyl) protection of the compound 2 or 4. Under the room temperature condition, compound 2 or 4 is dissolved in methanol or ethanol or isopropanol, then under the protection of nitrogen [...] diacetic acid [PhI (OAc)2 ] Oxidation to obtain compound 3 or 5. In the three ethylene diamine (DABCO) as catalyst and polyethylene glycol (PEG - 400) as reaction solvent 40 o C conditions, compound 5 with compound 6 in 1, 4 - conjugate addition reaction/sulfonylimines acylation reaction asymmetric structure dihalodiarylsulfone 7. The raw material is cheap and easy to obtain, reaction selectivity, and reaction solvent polyethylene glycol (PEG - 400) can be recycled 4 - 5 times less environmental pollution, high yield and easy application and the like. (by machine translation)
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Paragraph 0021; 0023
(2018/11/27)
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- An Efficient Coupling of p-Quinone Mono-Imine Ketals and Aryl/Alkyl Thiols: Rapid Synthesis of Biaryl/Aryl–Alkyl Sulfides
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We report a fast, efficient, and metal-free protocol for the synthesis of unsymmetrical biaryl sulfides and aryl–alkyl sulfides (4-methoxy-2-sulfanyl-phenylcarbamates) under catalytic influence of 2,4-dinitrobenzoic acid. The reaction proceeded in a regioselective anti-Michael addition fashion and all the products were obtained within a very short period of time and in good to excellent yields.
- Sharma, Arun,Peddinti, Rama Krishna
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p. 2230 - 2237
(2017/05/01)
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- Efficient Synthesis of Unsymmetrical Sulfamides via a Lossen-Like Rearrangement
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A convenient one-pot synthesis of unsymmetrical sulfamides via a Lossen-like rearrangement is reported. The protocol operates under simple conditions at room temperature and does not require an inert atmosphere and a dry solvent. The ability of N-hydroxy arenesulfonamide O-derivatives to generate under mild conditions N-sulfonylimine intermediates was a trigger point for developing a general synthetic strategy towards unsymmetrical sulfamides. The synthetic potential of the methodology has been investigated by preparing cyclic sulfamides and new potential chiral organocatalysts. (Figure presented.) .
- Pantaine, Lo?c,Richard, Fran?ois,Marrot, Jér?me,Moreau, Xavier,Coeffard, Vincent,Greck, Christine
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supporting information
p. 2012 - 2016
(2016/07/06)
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- Axially chiral dicarboxylic acid catalyzed activation of quinone imine ketals: Enantioselective arylation of enecarbamates
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The synthetic utility of quinone imine ketals in the context of asymmetric catalysis was disclosed for the first time. By expanding the utility of chiral Bronsted acid catalysis to the electrophilic activation of quinone imine ketals, we succeeded in the development of highly enantioselective arylation of encarbamates to give α-amino-β-aryl ethers wherein quinone imine ketals act as functionalized aromatic ring surrogate. Further transformations of the products were also examined to establish procedures to provide chiral β-aryl amines and α-aryl esters.
- Hashimoto, Takuya,Nakatsu, Hiroki,Takiguchi, Yuka,Maruoka, Keiji
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supporting information
p. 16010 - 16013
(2013/11/19)
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- Hypervalent iodine mediated synthesis of carbamate protected p-quinone monoimine ketals and p-benzoquinone monoketals
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A simple and efficient method for the synthesis of p-quinone monoimide ketals and p-benzoquinone monoketals by using a hypervalent iodine reagent, diacetoxyiodobenzene, has been developed. These two types of ketals are achieved from a single starting material by varying the reaction conditions.
- Bodipati, Naganjaneyulu,Peddinti, Rama Krishna
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experimental part
p. 4549 - 4553
(2012/07/14)
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- Synthesis of 4-aminotropones from [(sulfinyl or sulfonyl)methyl]- substituted p-quinamines
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An efficient synthesis of 4aminotropones has been achieved in excellent yields by simple treatment of 4-amino-4-[(p-tolylsulfinyl)methyl]-2, 5cyclohexadienones (p-quinamines) with NaH. The method allowed regiocontrolled access to 3-methyl, 5-methyland 3,5
- Carreno, M. Carmen,Ortega-Guerra, Montserrat,Ribagorda, Maria,Sanz-Cuesta, M. Jesus
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p. 621 - 636
(2008/12/21)
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- Ring expansion of sulfur substituted p-quinamines: Regiospecific synthesis of 4-aminotropones
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Synthesis of 4-aminotropones through a cyclization-ring expansion process occurs in a single step and with excellent yields from 4-amino-2,5- cyclohexadienones (p-quinamines) bearing a 4-sulfinyl or sulfonyl methyl group. The Royal Society of Chemistry 20
- Carreno, M. Carmen,Sanz-Cuesta, M. Jesus,Ribagorda, Maria
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p. 1007 - 1009
(2007/10/03)
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