- The development of efficient protocols for the palladium-catalyzed cyclization reactions of secondary amides and carbamates
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(equation presented) With the proper choice of palladium catalyst, ligand, and base, five-, six-, and seven-membered rings are formed efficiently from secondary amide or secondary carbamate precursors, offering significant improvements to currently existing methodology.
- Yang, Bryant H.,Buchwald, Stephen L.
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- Synthesis of Chiral 2-Substituted 1,4-Benzoxazin-3-ones via Iridium-Catalyzed Enantioselective Hydrogenation of Benzoxazinones
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An efficient iridium-catalyzed enantioselective hydrogenation of 2-alkylidene 1,4-benzoxazin-3-ones using our developed iPr-BiphPHOX as a ligand is reported. This method showed good functional group compatibility and delivered the corresponding reduced products in excellent yields (up to 99%) with excellent enantioselectivities (up to 99% ee). The reaction proceeded very well on a gram scale with low catalyst loadings (0.1 mol %), providing the product with no erosion in enantioselectivity. Additionally, three bioactive molecules can be easily obtained from the reduced products.
- Nie, Yu,Li, Jing,Yan, Jun,Yuan, Qianjia,Zhang, Wanbin
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supporting information
p. 5373 - 5377
(2021/07/26)
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- Redox-Triggered Switchable Synthesis of 3,4-Dihydroquinolin-2(1 H)-one Derivatives via Hydride Transfer/ N-Dealkylation/ N-Acylation
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The switchable synthesis of 3-non, 3-mono, 3,3′-disubstituted 3,4-dihydroquinolin-2(1H)-ones was developed through a redox-neutral hydride-transfer/N-dealkylation/N-acylation strategy from o-aminobenzaldehyde with 4-hydroxycoumarin, and Meldrum's acid, respectively. The unprecedented strategy for the synthesis of 3,3′-highly functionalized 3,4-dihydroquinolin-2(1H)-one has been realized with the in situ utilization of the released HCHO via the o-QM involved Michael addition. In addition, the synthetic utility of this protocol has been well illustrated via concise synthesis of CYP11B2 inhibitor.
- Hu, Fangzhi,Li, Sanming,Li, Shuai-Shuai,Wang, Liang,Xu, Lubin,Yang, Xiaoyu
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supporting information
p. 358 - 364
(2021/01/13)
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- 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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- NIS-mediated oxidative arene C(sp2)-H amidation toward 3,4-dihydro-2(1H)-quinolinone, phenanthridone, and N-fused spirolactam derivatives
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A new radical-mediated intramolecular arene C(sp2)-H amidation of 3-phenylpropanamides or [1,1′-biphenyl]-2-carboxamides was developed to prepare a series of 3,4-dihydro-2(1H)-quinolinone and phenanthridone derivatives in moderate to excellent yields (33-94%). Spirolactams could also be obtained using this protocol.
- Wu, Lingang,Hao, Yanan,Liu, Yuxiu,Wang, Qingmin
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p. 6762 - 6770
(2019/07/22)
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- Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines
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The synthesis of novel tetrahydroquinolines (THQ) and dihydroquinolines (DHQ) are reported using three practical, scalable synthetic approaches to access highly lipophilic analogues bearing a 6-iodo substituent, each with a different means of cyclisation. A versatile and stable quinolin-2-one intermediate was identified, which could be reduced to the corresponding THQ with borane reagents, or to the DHQ with diisobutylaluminium hydride via a novel elimination that is more favourable at higher temperatures. Coupling these strongly electron-donating scaffolds to electron-accepting moieties caused the resulting structures to exhibit strong fluorescence.
- Chisholm, David R.,Zhou, Garr-Layy,Pohl, Ehmke,Valentine, Roy,Whiting, Andrew
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supporting information
p. 1851 - 1862
(2016/10/05)
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- Synthesis of novel phenylnaphthyl phosphines and their applications to Pd-catalyzed intramolecular amidation
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Novel phenylnaphthyl phosphines were prepared and applied to the Pd-catalyzed intramolecular amidation. Both ligands gave good to excellent yields in the synthesis of five-, six-, and seven-membered rings from halo-amides and carbamates. Georg Thieme Verl
- Kitamura, Yuki,Hashimoto, Ayano,Yoshikawa, Seiji,Odaira, Jun-Ichi,Furuta, Takumi,Kan, Toshiyuki,Tanaka, Kiyoshi
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p. 115 - 117
(2007/10/03)
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- Intramolecular palladium-catalyzed aryl amination and aryl amidation
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Upon treatment with a palladium catalyst and a suitable base, aromatic halides undergo intramolecular substitution to form five, six, and seven-membered rings. In a similar fashion aryl halides with pendant amides or sulfonamides are cyclized to form five and six-membered rings.
- Wolfe, John P.,Rennels, Roger A.,Buchwald, Stephen L.
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p. 7525 - 7546
(2007/10/03)
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- Synthesis of 3,4-dihydroisoquinolines, 2-alkyl(acyl)-1(2H)-3,4-dihydroisoquinolinones, 2-alkyl-1(2H)-isoquinolinones and 1-alkyl-2(2H)-quinolinones by oxidation with potassium permanganate
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Synthesis of 3,4-dihydroisoquinolines 2, 2-alkyl- 6 and 2-acyl-3,4-dihydro-1(2H)-isoquinolinones 9, 2-alkyl-1(2H)-isoquinolinones 14, N-alkyl-3,4-dihydro-2(2H)-quinolinones 16 and N-alkyl-2(2H)-quinolinones 19 by oxidation of 1,2,3,4-tetrahydroisoquinolines 1, N-alkyl (acyl)iminium salts of 3,4-dihydroisoquinolines 5,8 and isoquinoline 13 as well as of N-alkyl ammonium salts of tetrahydroquinoline 15 and quinoline 18 with potassium permanganate is described.
- Venkov,Statkova-Abeghe
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p. 1451 - 1460
(2007/10/03)
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- ISOMERIZING RECYCLIZATION OF QUATERNARY SALTS OF ETHYL 3-(2-PYRIDYL)BUTYRATE AND DIETHYL 2-(2-PYRIDYL)ETHYLMALONATE
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A number of quaternary salts of ethyl γ-pyridylbutyrate and diethyl β-pyridylethylmalonate undergo the Kost-Sagitullin reaction to give N-methyl-2-quinolone and 3-methylaminocarbamoyl-N-methyl-2-quinolone.Rearrangement in the presence of excess aliphatic amines is accompanied by an efficiently proceeding trans-amination.
- Ignatchenko, A. V.,Terent'ev, P. B.
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p. 292 - 295
(2007/10/02)
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- ELECTROREDUCTIVE N-ALKYLATION OF AMIDES, CARBAMATES, AND N-HETEROCYCLES
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The N-alkylation of amides, lactams, carbamates, and N-heterocycles was easily attained in good yields by the electroreduction of the substrates in the presence of alkyl halides.
- Shono, Tatsuya,Kashimura, Shigenori,Nogusa, Hideo
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p. 425 - 428
(2007/10/02)
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- SN2 Reactions of Nitranions with Benzyl Chlorides
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The rates of SN2 reactions of 19 nitranions with PhCH2Cl and 9 nitranions with m-CF3C6H4CH2Cl were measured in Me2SO at 25 deg C.Bronsted plots of log k vs. pKHA for reactions of anion families derived from carbazoles, phenothiazines, and diphenylamines with PhCH2Cl are linear with slopes of 0.32-0.33.Extension of the carbazole and phenothiazine family lines, which are collinear, provided a reference line by which nucleophilicities of other nitranions could be assessed at constant basicity.Nitranions of varied structural types were found to have remarkably similar nucleophilicities when compared at the same basicities.Steric effects caused rates of reactions of ArAr'N(1-) ions and acetanilide ion to be retarded slightly and that of benzanilide ion to be retarded appreciably.Evidence is presented to show that nitranions, like carbanions, utilize the electron pair in a p orbital for bonding to an electrophile whereas pyridines utilize a nonbonded electron pair.Comparisons with literature data for neutral nitrigen nucleophiles, such as n-BuNH2 and PhNH2, indicate that they are 10-100 times more reactive than nitranion nucleophiles of comparable basicity.The order of nucleophilicities toward PhCH2Cl of anion families with different donor atoms when compared at the same basicity was found to be the following: 9-methylfluoredine ion family (25) > 2-naphthoxide ion family (3) > carbazole ion family (1.0).The results show that basicity is the primary factor in controlling nucleophilicities of nitranions, carbanions, and oxanions of diverse structural types in SN2 reactions.Donor atom, solvation, and steric effects generally play a secondary role.
- Bordwell, Frederick G.,Hughes, David L.
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p. 3234 - 3240
(2007/10/02)
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