875-30-9Relevant academic research and scientific papers
A photolabile 'traceless' linker for solid-phase organic synthesis
Horton,Stamp,Routledge
, p. 9181 - 9184 (2000)
A photolabile linker based on a thiohydroxamic acid has been shown to be efficient 'traceless' linker, revealing an aliphatic CH bond on photolysis at 350 nm. Methods for the synthesis, loading and phtolytic cleavage of the linker are described. (C) 2000 Elsevier Science Ltd.
Synthesis of 3-halogenated 2,3′-biindoles by a copper-mediated 2,3-difunctionalization of indoles
Gu, Xiaoting,Liang, Taoyuan,Wei, Wanxing,Zhang, Xiaoxiang,Zhang, Yingying,Zhang, Zhuan
supporting information, p. 10403 - 10407 (2021/12/17)
A copper-mediated 2,3-difunctionalization of indoles to afford 3-halogenated 2,3′-biindoles is described herein. The protocol uses readily available feedstocks and a naturally abundant copper catalyst system, which allows the regioselective formation of C-C and C-X (X = Cl & Br) bonds in one single operation. Here the copper metal salt serves not only as a catalyst but also as a reactant to provide the source of halogen. This operationally simple procedure avoids the utilization of environmentally unfriendly reagents and displays good functional group compatibility. Noteworthily, the introduction of halogen into molecules would offer great potential for further chemical transformations. This journal is
Electrochemical Umpolung C-H Functionalization of Oxindoles
Maulide, Nuno,Pastor, Miryam,Vayer, Marie,Weinstabl, Harald
supporting information, (2022/01/12)
Herein, we present a general electrochemical method to access unsymmetrical 3,3-disubstituted oxindoles by direct C-H functionalization where the oxindole fragment behaves as an electrophile. This Umpolung approach does not rely on stoichiometric oxidants and proceeds under mild, environmentally benign conditions. Importantly, it enables the functionalization of these scaffolds through C-O, and by extension to C-C or even C-N bond formation.
Preparation method of nitrogen-alkyl (deuterated alkyl) aromatic heterocycle and alkyl (deuterated alkyl) aryl ether compound
-
Paragraph 0048-0050, (2021/04/03)
The invention provides a method for preparing nitrogen-alkyl(deuterated alkyl)aromatic heterocycle and alkyl(deuterated alkyl)aryl ether compounds. The method adopted in the invention specifically comprises the following steps: firstly, adding an alkoxy base (MOR') or a combination reagent Q (comprising a base M'X, an alcohol C and a molecular sieve E) into a solvent B to be stirred; then, addingan aromatic compound D of nitrogen sulfonyl or oxygen sulfonyl into a mixture; separating and purifying after reaction to obtain nitrogen-alkyl(deuterated alkyl)aromatic heterocycle or alkyl(deuterated alkyl)aryl ether. The method can realize one-step conversion from an electron withdrawing benzenesulfonyl protecting group on a nitrogen or oxygen atom to an electron donating alkyl protecting group, avoids using highly toxic alkyl halide, and has advantages of being efficient, economical, environmentally friendly, mild in condition, good in substrate universality and high in yield; the prepareddeuterated compounds can be widely applied to the fields of pharmaceutical chemistry and organic chemistry synthesis.
Solid-State Radical C?H Trifluoromethylation Reactions Using Ball Milling and Piezoelectric Materials
Ito, Hajime,Kubota, Koji,Lee, Joo Won,Pang, Yadong
supporting information, p. 22570 - 22576 (2020/10/21)
The application of piezoelectricity for the generation of trifluoromethyl (CF3) radicals is reported together with the development of a method for the mechanochemical C?H trifluoromethylation of aromatic compounds. As compared to conventional solution-based approaches, this mechanoredox C?H trifluoromethylation enables cleaner and more sustainable access to a wide range of trifluoromethylated N-heterocycles and peptides, which are important structural motifs in modern drug discovery. This study thus represents an important milestone for future applications of mechanoredox systems to medicinal and pharmaceutical science.
Tethered Counterion-Directed Catalysis: Merging the Chiral Ion-Pairing and Bifunctional Ligand Strategies in Enantioselective Gold(I) Catalysis
Frison, Gilles,Guinchard, Xavier,Marinetti, Angela,Retailleau, Pascal,Smal, Vitalii,Voituriez, Arnaud,Zhang, Zhenhao
supporting information, p. 3797 - 3805 (2020/03/10)
Tethering a metal complex to its phosphate counterion via a phosphine ligand enables a new strategy in asymmetric counteranion-directed catalysis (ACDC). A straightforward, scalable synthetic route gives access to the gold(I) complex of a phosphine displaying a chiral phosphoric acid function. The complex generates a catalytically active species with an unprecedented intramolecular relationship between the cationic Au(I) center and the phosphate counterion. The benefits of tethering the two functions of the catalyst are demonstrated here in a tandem cycloisomerization/nucleophilic addition reaction, by attaining high enantioselectivity levels (up to 97% ee) at an unusually low 0.2 mol % catalyst loading. Remarkably, the method is also compatible with a silver-free protocol.
Synthesis of pyrroloindolines through formal [3 + 2]-cycloaddition of indoles with chiral N-2-acetamidoacrylyl oxazolidinones
Smith, Isaac T.,Neeley, Jared B.,Brinley, Tanner D.,Fullmer, Peter R.,Andrus, Merritt B.
supporting information, (2020/05/01)
Chiral N-2-acetamidoacrylyl oxazolidinones were produced and reacted with indoles under Lewis acid conditions to generate hexahydropyrrolo[2,3-b]indole products in a formal [3 + 2] cycloaddition process. Optimal conditions included the use of tin(IV) chloride in methylene chloride at 0 °C. Pyrroloindoline products were obtained from various indoles with shorter reaction times (12 hr) up to 91% yield with high, >20:1 exo selectivity. A mechanism involving reversible conjugate addition followed by an enamine lone-pair-iminium capture, tautomerization, and tin-enolate protonation accounts for the selectivity. The method enables selective applications to pyrroloindoline targets and further refinement with chiral catalysts.
Sulfoxide-Promoted Chlorination of Indoles and Electron-Rich Arenes with Chlorine as Nucleophile
Ji, Yuan-Zhao,Li, Hui-Jing,Wang, Yi-Ruo,Wu, Yan-Chao,Zhang, Zheng-Yan
supporting information, (2020/02/05)
An efficient chlorination of indoles and electron-rich arenes with chlorine anion as nucleophile is described. With the use of ethyl phenyl sulfoxide as the promoter, the reaction went smoothly under metal-free and mild conditions. Various indoles and electron-rich arenes are converted into the corresponding chlorinated compounds in moderate to excellent yields. A plausible interrupted Pummerer reaction mechanism was proposed without the oxidation of chloride anion. In addition, the byproduct thioether could be easily converted to the starting material sulfoxide just by a simple oxidation reaction. (Figure presented.).
Ascorbic Acid as an Aryl Radical Inducer in the Gold-Mediated Arylation of Indoles with Aryldiazonium Chlorides
Medina-Mercado, Ignacio,Asomoza-Solís, Eric Omar,Martínez-González, Eduardo,Ugalde-Saldívar, Victor Manuel,Ledesma-Olvera, Lydia Gabriela,Barquera-Lozada, José Enrique,Gómez-Vidales, Virginia,Barroso-Flores, Joaquín,Frontana-Uribe, Bernardo A.,Porcel, Susana
supporting information, p. 634 - 642 (2019/12/11)
In recent years interest in the development of protocols that facilitate the oxidative addition of gold to access mild cross-coupling processes mediated by this metal has increased. In this context, we report herein that ascorbic acid, a natural and readily accessible antioxidant, can be used to accelerate the oxidative addition of aryldiazonium chlorides onto AuI. The aryl–AuIII species generated in this way, has been used to prepare 3-arylindoles in a one-pot protocol starting from anilines and para-, meta-, and ortho- substituted aryldiazonium chlorides. The mechanism underlying the oxidative addition has been examined in detail based on EPR analyses, cyclic voltammetry, and DFT calculations. Interestingly, we have found that in this protocol, the chloride atom induces the AuII/AuIII oxidation step.
Synthesis of Pyrido[2,3-b]indole Derivatives via Rhodium-Catalyzed Cyclization of Indoles and 1-Sulfonyl-1,2,3-triazoles
An, Yuehui,Chen, Yidian,Duan, Shengguo,Li, Chuan-Ying,Xu, Ze-Feng,Xue, Bing,Zhang, Wan
supporting information, (2020/04/22)
Acyloxy-substituted α,β-unsaturated imines generated in situ from triazoles can act as aza-[4 C] synthons and be trapped by indoles in a stepwise [4 + 2] cycloaddition reaction, thus providing rapid access to valuable pyrido[2,3-b]indoles in high yields. Attractive features of this reaction system include operational simplicity, readily available substrates, construction of sterically demanding quaternary centers, and convenient derivatization using triflate. (Figure presented.).
