- Nickel/Photo-Cocatalyzed Asymmetric Acyl-Carbamoylation of Alkenes
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An unprecedented asymmetric acyl-carbamoylation of pendant alkenes tethered on aryl carbamic chlorides with both aliphatic and aromatic aldehydes has been developed via the cooperative catalysis of a chiral nickel-PHOX complex and tetrabutylammonium decatungstate. This reaction represents the first example of merging hydrogen-atom-transfer photochemistry and asymmetric transition metal catalysis in difunctionalization of alkenes. Using this protocol, a variety of oxindoles bearing a challenging quaternary stereogenic center are furnished under mild conditions in highly enantioselective manner.
- Fan, Pei,Lan, Yun,Zhang, Chang,Wang, Chuan
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p. 2180 - 2186
(2020/03/03)
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- Site-Selective Linear Alkylation of Anilides by Cooperative Nickel/Aluminum Catalysis
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We report meta- and para-selective linear alkylation reactions of anilides with alkenes by nickel/N-heterocyclic carbene (NHC) and aluminum catalysis. With a less bulky NHC, the alkylation reaction of N-methyl-N-phenylcyclohexanecarboxamides proceeded mainly at the meta position. In contrast, a bulky NHC ligand led to the para-selective alkylation of N-sec-alkyl anilides.
- Okumura, Shogo,Komine, Takuya,Shigeki, Erika,Semba, Kazuhiko,Nakao, Yoshiaki
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supporting information
p. 929 - 932
(2017/12/26)
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- C–C bond-forming reactions of ground-state aryl halides under reductive activation
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Under basic conditions aryl halides can undergo SRN1 reactions, BHAS reactions and benzyne formations. Appropriate complex substrates afford an opportunity to study inherent selectivities. SRN1 reactions are usually favoured under ph
- Emery, Katie J.,Tuttle, Tell,Kennedy, Alan R.,Murphy, John A.
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p. 7875 - 7887
(2016/11/17)
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- Visible-light-mediated reaction: Synthesis of quinazolinones from 1,2-dihydroquinazoline 3-oxides
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1-Methyl-2-phenylquinazolin-4(1H)-ones were synthesized in good yield by exposing 1,4-dimethyl-2-phenyl-1,2-dihydroquinazoline 3-oxides or 1-methyl-2-phenyl-1,2-dihydroquinazoline 3-oxides to visible light in acetonitrile in the absence of any external ph
- Wu, Chun-Ku,Yang, Ding-Yah
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p. 65988 - 65994
(2016/07/26)
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- Silica gel-mediated hydroamination/semipinacol rearrangement of 2-alkylaminophenylprop-1-yn-3-ols: Synthesis of 2-oxindoles from alkynes and 1-(2-aminophenyl) ketones
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2-Alkylaminophenylprop-1-yn-3-ols, prepared from the lithium diisopropylamide (LDA)- mediated 1,2-addition of alkynes to 1-(2-aminophenyl) ketones, can be converted to 3,3-disubstituted 2-oxindoles by using silica gel in n-hexane/ ethyl acetate (20:1 v/v) as the reaction medium. The utility of the approach as a potential scale-up strategy for the synthesis of 2-oxindoles was exemplified by the large-scale synthesis of one adduct in excellent yield. The synthetic applicability of this chemistry was also demonstrated by the recycling of the silica gel up to 8 times with no apparent loss of activity being observed for the same example.
- Susanti, Dewi,Ng, Linda Li Ru,Chan, Philip Wai Hong
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supporting information
p. 353 - 358
(2014/05/20)
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- Copper-catalyzed intramolecular oxidative C(sp3)-H amidation of 2-aminoacetophenones: Efficient synthesis of indoline-2,3-diones
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An efficient synthesis of diverse indoline-2,3-diones from 2-aminoacetophenones through copper-catalyzed intramolecular C(sp3)-H amidation is developed. The reaction proceeds in DMSO by using O2 as the sole oxidant to provide the desired products in moderate to good yields.
- Huang, Jinbo,Mao, Tingting,Zhu, Qiang
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supporting information
p. 2878 - 2882
(2014/05/20)
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- Asymmetric synthesis of 1,3-diamines. II: Diastereoselective reduction of atropisomeric N-tert -butanesulfinylketimines
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Chiral, nonracemic o-aminobenzylamines were prepared in a highly diastereoselective reduction of atropisomeric N-tert-butanesulfinylketimines. The ortho-substituent ensures the distinct reactivity of atropisomers 4d-f. The free energy of activation for at
- Martjuga, Marina,Belyakov, Sergey,Liepinsh, Edvards,Suna, Edgars
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experimental part
p. 2635 - 2647
(2011/06/20)
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- Evolution from a natural flavones nucleus to obtain 2-(4-propoxyphenyl) quinoline derivatives as potent inhibitors of the S. aureus NorA efflux pump
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Overexpression of efflux pumps is an important mechanism by which bacteria evade the effects of substrate antimicrobial agents. Inhibition of such pumps is a promising strategy to circumvent this resistance mechanism. NorA is a Staphylococcus aureus efflux pump that confers reduced susceptibility to many structurally unrelated agents, including fluoroquinolones, resulting in a multidrug resistant phenotype. In this work, a series of 2-phenyl-4(1H)- quinolone and 2-phenyl-4-hydroxyquinoline derivatives, obtained by modifying the flavone nucleus of known efflux pump inhibitors (EPIs), were synthesized in an effort to identify more potent S. aureus NorA EPIs. The 2-phenyl-4- hydroxyquinoline derivatives 28f and 29f display potent EPI activity against SA-1199B, a strain that overexpresses norA, in an ethidium bromide efflux inhibition assay. The same compounds, in combination with ciprofloxacin, were able to completely restore its antibacterial activity against both S. aureus SA-K2378 and SA-1199B, norA-overexpressing strains.
- Sabatini, Stefano,Gosetto, Francesca,Manfroni, Giuseppe,Tabarrini, Oriana,Kaatz, Glenn W.,Patel, Diixa,Cecchetti, Violetta
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experimental part
p. 5722 - 5736
(2011/10/09)
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- A practical, metal-free synthesis of 1H-Lndazoles
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The synthesis of 1H-indazoles is achieved from o-aminobenzoximes by the selective activation of the oxime in the presence of the amino group. The reaction occurs with a variety of substituted o-aminobenzoximes using a slight excess of methanesulfonyl chloride and triethylamine at 0-23 °C and is amenable to scale-up. The synthesis of 1 H-indazoles under these conditions is extremely mild compared with previous synthetic approaches and affords the desired compounds in good to excellent yields.
- Counceller, Carla M.,Eichman, Chad C.,Wray, Brertda C.,Stambuli, James P.
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supporting information; experimental part
p. 1021 - 1023
(2009/04/07)
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- Regioselective synthesis of silylated pyrazolines and indazolines by reaction of pyrazolium and indazolium salts with silyllithium reagents
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Pyrazolium salts react with dimethylphenylsilyl- and tert- butyldiphenylsilyllithium to give, in general, only one of the two possible 5-silyl-3-pyrazolines. On the other hand, indazolium and isoindazolium salts lead to 3-silylindazolines and occasionally
- Gonzalez-Nogal, Ana M.,Calle, Mariola,Calvo, Luis A.,Cuadrado, Purificacion,Gonzalez-Ortega, Alfonso
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p. 4663 - 4669
(2007/10/03)
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- A novel intramolecular photocyclization of N-(2-bromoalkanoyl) derivatives of 2-acylanilines via 1,8-hydrogen abstraction
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The photochemical reactions of different N-(2-acylphenyl)-2-bromo-2- methylpropanamides have been investigated. Irradiation of the N-unsubstituted anilides 1a-1c gave the corresponding dehydrobromination, cyclization, and bromo-migration products 2, 3, and 4, respectively (Table 1). Irradiation of the N-alkyl anilides 1e-1g afforded the corresponding deacylation and cyclization products 5 and 6, respectively, whereas irradiation of the N-alkyl anilides 1i-1k, carrying 2-benzoyl groups on the aromatic rings, afforded the unexpected tricyclic lactams 7 (besides 2, 5, and 6). The formation of the cyclization products 6 could be rationalized in terms of an electrocyclic ring closure of the 6π-electron-conjugated enamides 2 produced by dehydrobromination of 1, followed by thermal 1,5-acyl migration (Path B in the Scheme). The formation of the bridged lactams 7 probably follows a mechanism involving the 1,7-diradical 8 generated by ζ-H-abstraction (1.8-H transfer) by an excited acyl O-atom (Path A).
- Nishio, Takehiko,Koyama, Hiroyuki,Sasaki, Daigo,Sakamoto, Masami
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p. 996 - 1003
(2007/10/03)
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- Electrosynthesis of 3-chloro-1,4-disubstituted-2(1H)-quinolinones and 3,3-dichloro-4-hydroxy-1,4-disubstituted-3,4-dihydro-2(1H)-quinolinones, as well as a new convenient process to dioxindoles
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Cathodic reduction of N-(2-acyl(or aroyl)phenyl)-2,2,2,-trichloro-N-alkylacetamide at - 1.2 V (vs SCE) under aprotic conditions yields 3-chloro-1,4-disubstituted-2(1H)-quinolinones (1) as the major product. When the reaction is carried out at -0.8 V (vs S
- Batanero, Belen,Barba, Fructuoso
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p. 3706 - 3709
(2007/10/03)
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- Ring closing and photooxidation in nitrogen analogues of 3-hydroxyflavone
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An epoxide intermediate in the Algar-Flynn-Oyamada (AFO) synthesis of flavones is reaffirmed through the use of quinolone analogues to 3-hydroxyflavone (3HF).Stepwise synthesis of analogues 3-hydroxy-2-phenyl-1,4-dihydro-4-quinolone 11 and 3-hydroxy-1-methyl-2-phenyl-1,4-dihydro-4-quinolone 12, via chalcone formation, epoxidation, ring closing and final oxidation, has been accomplished.The intermediacy of an epoxide is further supported by blocking cyclization with methoxy substitution at the 2'-position (1A).Absorption/emission spectroscopy of 11 and 12 shows large red shifts, as seen in 3HF, indicative of an excited state intramolecular proton transfer mechanism.Nitrogen analogues demonstrate photooxidative stability similar to that of 3HF.
- Gao, Feng,Johnson, Kurtis F.,Schlenoff, Joseph B.
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p. 269 - 274
(2007/10/03)
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- Photogenerated arylnitrenium ions: Photoisomerization of the N-tert-butyl-S-methylanthranilium ion and spin-selective reactivity of the isomeric arylnitrenium ion
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The photochemical behavior of the N-tert-butyl-3-methylanthranilium ion was examined with the goal of understanding the chemical behavior of the intermediate nitrenium ion. Trapping experiments show that the corresponding nitrenium ion is generated throug
- Anderson, Gary B.,Yang, Lucie L.-N.,Falvey, Daniel E.
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p. 7254 - 7262
(2007/10/02)
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- Chiral Building Blocks for the Synthesis of Nitrogen-Containing Natural Products, 5. The Enantioselective Synthesis of Optically Active, Benzene Nucleus-Substituted 1-Phenylethylamines from the Corresponding Acetophenones
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An efficient two-step procedure for the synthesis of enantiomerically pure, benzene nucleus-substituted 1-phenylethylamines 1 is described, with predictable absolute configuration at the stereogenic center: Imine formation from the substituted acetophenones 6 with (S)- or (R)-1-phenylethylamine and subsequent hydrogenation of the resulting Schiff bases 8 over Raney nickel leads to the secondary amines 9 and 10 in high diastereoselectivities.These dibenzylamines are cleaved regioselectively, usually next to the less substituted aromatic ring, giving the desired chiral 1-phenylethylamines 1 in high yields and enantiomeric purities.Scope and limitations of this new and facile approach to the versatile building blocks 1 are reported.
- Bringmann, Gerhard,Geisler, Joerg-Peter,Geuder, Torsten,Kuenkel, Georg,Kinzinger Lioba
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p. 795 - 805
(2007/10/02)
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- OXIDATION OF 2-INDOLINONES WITH COBALT(II) SCHIFF'S BASE COMPLEXES
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The oxidation of 2-indolinones (1) catalysed with cobalt(II) Schiff's base complexes gave isatins (2), O-aminoketones (3), 3-hydroxy-2-indolinones (4), and dimers (5).
- Inada, Akira,Morita, Yutaka
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p. 2139 - 2142
(2007/10/02)
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