- Synthesis of CF3-Containing Spirocyclic Indolines via a Red-Light-Mediated Trifluoromethylation/Dearomatization Cascade
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A red-light-mediated nPr-DMQA+-catalyzed cascade intramolecular trifluoromethylation and dearomatization of indole derivatives with Umemoto's reagent has been developed. This protocol provides a facile and efficient approach for the construction of functionalized and potentially biologically important CF3-containing 3,3-spirocyclic indolines with moderate to high yields and excellent diastereoselectivities under mild conditions. The success of multiple gram-scale (1 and 10 g) experiments further highlights the robustness and practicality of this protocol and the merit of the employment of red light. Mechanistic studies support the formation of a crucial CF3 radical species and a dearomatized benzyl carbocation intermediate.
- Gianetti, Thomas L.,Mei, Liangyong,Moutet, Jules,Stull, Savannah M.
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supporting information
p. 10640 - 10653
(2021/07/31)
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- Enantio- and Site-Selective α-Fluorination of N-Acyl 3,5-Dimethylpyrazoles Catalyzed by Chiral π–CuII Complexes
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Catalytic enantioselective α-fluorination reactions of carbonyl compounds are among the most powerful and efficient synthetic methods for constructing optically active α-fluorinated carbonyl compounds. Nevertheless, α-fluorination of α-nonbranched carboxylic acid derivatives is still a big challenge because of relatively high pKa values of their α-hydrogen atoms and difficulty of subsequent synthetic transformation without epimerization. Herein we show that chiral copper(II) complexes of 3-(2-naphthyl)-l-alanine-derived amides are highly effective catalysts for the enantio- and site-selective α-fluorination of N-(α-arylacetyl) and N-(α-alkylacetyl) 3,5-dimethylpyrazoles. The substrate scope of the transformation is very broad (25 examples including a quaternary α-fluorinated α-amino acid derivative). α-Fluorinated products were converted into the corresponding esters, secondary amides, tertiary amides, ketones, and alcohols with almost no epimerization in high yield.
- Ishihara, Kazuaki,Nishimura, Kazuki,Yamakawa, Katsuya
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p. 17641 - 17647
(2020/08/14)
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- Radical-Mediated Dearomatization of Indoles with Sulfinate Reagents for the Synthesis of Fluorinated Spirocyclic Indolines
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The dearomative introduction of trifluoromethyl and 1,1-difluoroethyl radicals, generated from their corresponding sulfinate salts, into the C2 position of indole derivatives allows the diastereoselective synthesis of three-dimensional 3,3-spirocyclic indolines over C-H functionalized indoles.
- Ryzhakov, Dmytro,Jarret, Maxime,Guillot, Régis,Kouklovsky, Cyrille,Vincent, Guillaume
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supporting information
p. 6336 - 6339
(2017/12/08)
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- Synthesis of tripeptides as potent Yersinia protein tyrosine phosphatase inhibitors
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We report the synthesis of a series of monoanionic phosphotyrosyl (pTyr) mimetic-containing tripeptides based on 'Fmoc-Glu(OBn)-Xxx-Leu-amide' (where Xxx = pTyr mimetic) and their N-terminally modified derivatives. The inhibitory potencies of compounds were tested against YopH and human PTP1B enzymes. Several compounds exhibited noteworthy activity against both YopH and PTP1B. Among the N-terminally modified analogues, 5-methylindole derivative 30 was found to be the best moiety to replace base-labile Fmoc group. A mode of binding with YopH is proposed for tripeptides 21, 30, and 31.
- Lee, Kyeong,Boovanahalli, Shanthaveerappa K.,Nam, Ky-Youb,Kang, Sang-Uk,Lee, Mijeoung,Phan, Jason,Wu, Li,Waugh, David S.,Zhang, Zhong-Yin,Kyoung, Tai No,Jung, Jun Lee,Burke Jr., Terrence R.
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p. 4037 - 4042
(2007/10/03)
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- Preparation of β2-homotryptophan derivatives for β-peptide synthesis
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In view of the prominent role of the 1H-indol-3-yl side chain of tryptophan in peptides and proteins, it is important to have the appropriately protected homologs H-β2-HTrp-OH and H-β3-HTrp-OH (Fig.) available for incorporation in β-
- Micuch, Peter,Seebach, Dieter
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p. 1567 - 1577
(2007/10/03)
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