- Visible-Light Induced C(sp2)?H Amidation with an Aryl–Alkyl σ-Bond Relocation via Redox-Neutral Radical–Polar Crossover
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We report an approach for the intramolecular C(sp2)?H amidation of N-acyloxyamides under photoredox conditions to produce δ-benzolactams with an aryl-alkyl σ-bond relocation. Computational studies on the designed reductive single electron transfer strategy led us to identify N-[3,5-bis(trifluoromethyl)benzoyl] group as the most effective amidyl radical precursor. Upon the formation of an azaspirocyclic radical intermediate by the selective ipso-addition with outcompeting an ortho-attack, radical–polar crossover was then rationalized to lead to the rearomative ring-expansion with preferential C?C bond migration.
- Chang, Sukbok,Jeong, Jiwoo,Jung, Hoimin,Keum, Hyeyun,Kim, Dongwook
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p. 25235 - 25240
(2021/10/25)
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- Lewis Acid Mediated Tandem Reaction of Propargylic Alcohols with Hydroxylamine Hydrochloride to Give α,β-Unsaturated Amides and Alkenyl Nitriles
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We have developed a highly selective method for the synthesis of α,β-unsaturated amides and alkenyl nitriles from readily available propargylic alcohols. The reaction proceeded smoothly under the neutral conditions with hydroxylamine hydrochloride (NH2OH·HCl) as the nitrogen source. The development of these new strategies has significantly extended the application of hydroxylamine hydrochloride to the chemistry of propargylic alcohols. Moreover, both secondary and tertiary alcohols have been highly regioselectively transformed to the desired products with good functional group compatibility.
- Han, Ya-Ping,Song, Xian-Rong,Qiu, Yi-Feng,Hao, Xin-Hua,Wang, Jia,Wu, Xin-Xing,Liu, Xue-Yuan,Liang, Yong-Min
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p. 9200 - 9207
(2015/09/28)
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- TMSCl-mediated synthesis of α,β-unsaturated amides via C-C bond cleavage and C-N bond formation of propargyl alcohols with trimethylsilyl azide
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A new method with high efficiency for the synthesis of α,β- unsaturated amides from the easily prepared propargyl alcohols and TMSN 3 using TMSCl as an acid promoter is developed. A wide variety of α,β-unsaturated amides were produced in moderate to excellent yields. Mechanistic studies indicate that this transformation involves TMSCl-mediated allenylazide intermediate formation, C-C bond cleavage, and C-N bond formation. Significantly, this reaction shows good functional group compatibility and high regioselectivity, with a relatively short reaction time and inexpensive reagents.
- Song, Xian-Rong,Song, Bo,Qiu, Yi-Feng,Han, Ya-Ping,Qiu, Zi-Hang,Hao, Xin-Hua,Liu, Xue-Yuan,Liang, Yong-Min
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p. 7616 - 7625
(2014/09/16)
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- Direct transformation of arylpropynes to acrylamides via a three-step tandem reaction
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A novel and metal-free acrylamides formation between arylpropynes and hydroxylamine hydrochloride through sp3 C-H and C-C bond cleavage has been achieved with DDQ as an oxidant. The mechanistic study shows that the acrylamides are formed through a three-step tandem sequence, including cross-dehydrogenative-coupling (CDC) reaction, aza-Meyer-Schuster rearrangement and Beckmann rearrangement. This journal is The Royal Society of Chemistry 2014.
- Qiu, Jun,Zhang, Ronghua
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supporting information
p. 1556 - 1560
(2014/03/21)
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- Palladium-catalyzed intramolecular amidation of C(sp2)-H bonds: Synthesis of 4-aryl-2-quinolinones
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Figure presented A catalytic synthetic approach for the synthesis of 2-quinolinone compounds through a Pd-catalyzed C(sp2)-H functionalization/intramolecular amidation sequence is described. The cyclization process efficiently proceeds in the p
- Inamoto, Kiyofumi,Saito, Tadataka,Hiroya, Kou,Doi, Takayuki
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supporting information; experimental part
p. 3900 - 3903
(2010/07/05)
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- New base induced rearrangements of 4-acylisoxazolidines. Anionic reactional cascades from five membered rings to either four membered rings or open chain compounds
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Treatment of 2,3,3-triphenyl-4-formylisoxazolidines with bases triggers an unprecedented anionic reactional cascade which terminates with a 2-iminooxetane derivative. In the case of 2,3,3-triphenyl-4-methoxycarbonyl isoxazolidine the multistep rearrangement gives rise to a derivative of malonic acid.
- Gandolfi, Remo,Gamba, Anna,Presutto, Milena,Oberti, Roberta,Sardone, Nicola
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p. 917 - 920
(2007/10/03)
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- Reactivity of substituted and unsubstituted diphenylphosphonium diylides towards carbonic anhydride derivatives
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The reactivity of diphenylphosphonium diylides was investigated towards carbonic anhydric derivatives. Unsubstituted and substituted non-stabilized diylides react with phenylisocyanate and dicyclohexylcarbodiimide, leading to the formation of new monoylide type intermediates. These last ones react in situ with carbonyl compounds through a Wittig reaction leading respectively to α,β-unsaturated amides and amidines. Substituted semi-stabilized or stabilized diylides, in similar conditions lead to the formation of alkenes. In all the cases a high E stereoselectivity, determined by 1H-NMR and 13-C-NMR, was observed.
- Cristau,Taillefer,Urbani,Fruchier
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p. 2005 - 2020
(2007/10/03)
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- Condensation of Lithium Diphenylphosphonium Diylides with Carbonic Anhydride Derivatives. A New One-Pot Synthesis of α,β-Unsaturated Anilides and Amidines.
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Lithium diphenylphosphonium diylides readily attack phenylisocyanate and dicyclohexylcarbodiimide.The formed semi-stabilised ylides bear a metallated amide or amidine functium.Their use in situ as Wittig reagents towards aldehydes and ketones is shown to be a new one-pot, E-stereoselective synthesis for α,β-unsaturated anilides and amidines.Moreover, the corresponding phosphonium salts were isolated.Key Words: lithium phosphonium diylides; pseudo-acylation reaction; Wittig-reaction; vinylic amides and amidines.
- Cristau, Henri-Jean,Perraud-Darcy, Anne,Ribeill, Yves
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p. 2693 - 2696
(2007/10/02)
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- A New Route for the Synthesis of Coumarins, Thiacoumarins and Carbostyrils
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3-Arylcarbostyrils, coumarins and thiacoumarins (3) have been prepared from the respective β-aryl-α-bromodihydrocinnamoyl derivatives (2) by treatment with AlCl3.The β,β-diarylacrylic acid derivatives (4) and (9), obtained from 2, on reaction with AlCl3 afford 4-arylcarbostyrils (5) 6-methyl-4-phenylthiacoumarin (10) respectively.However the oxygen analogs (11) give 3,3-diphenyl-1-indanone (12)
- Natarajan, M.,Ramakrishnan, V. T.
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p. 720 - 727
(2007/10/02)
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