- Sulfanyl radical addition to alkynyl azides: An insight into vinyl radical cyclization onto the azido function
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5-Exo-Cyclization of 2-sulfanylvinyl radicals 16 and 21 is a fast process which prevents intramolecular addition to the sulfanyl aromatic ring and hydrogen abstraction. In contrast, the 2-sulfanylvinyl radicals 3 and 9 are reluctant to add to their alipha
- Montevecchi, Pier Carlo,Navacchia, Maria Luisa,Spagnolo, Piero
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- Byproduct promoted regioselective sulfenylation of indoles with sulfinic acids
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An unprecedented method to synthesise 3-sulfenylindoles is demonstrated via byproduct promoted sulfenylation of indoles with sulfinic acids in the absence of an external catalyst. The reaction selectively afforded structurally diverse indole thioethers in good to excellent yields in 1,2-dichloroethane at 80 °C. This journal is
- Liu, Cong-Rong,Ding, Liang-Hui
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- Aniline-initiated and Br?nsted acid-catalyzed one-pot reaction toward 2-aryl-3-sulfenylindoles by using α-aminocarbonyl compounds and primary amines with RSSR
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A highly novel method of direct synthesis of 2-aryl-3-sulfenylindoles in moderate to good yields was developed via one-pot tandem reaction of readily available α-aminocarbonyl compounds and catalytic amount of benzenamines with RSSR.
- Chen, De,Cheng, Chaozhihui,Deng, Wei,Guan, Wenjian,Liu, Yuxuan,Luo, Yongyue,Xiang, Jiannan,Zhang, Jiajia
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- Palladium-catalyzed three-component cascade arylthiolation with aryldiazonium salts asS-arylation sources
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A novel and efficient palladium-catalyzed three-component cascade cyclization/arylthiolation has been developed for the assembly of diverse 3-sulfenylindole and 3-sulfenylbenzofuran derivatives from 2-alkynylamines and 2-alkynylphenols, aryldiazonium salts, and Na2S2O3under aerobic conditions with PEG-200 as an environmentally benign medium. The current study features exceptional functional group tolerance without additional ligands, oxidants or silver salts, and eco-friendly mild reaction conditions. The ionic liquid [C2OHmim]Cl plays a crucial role in this protocol as an environmentally friendly additive. Notably, this procedure represents the first example of the use of aryldiazonium salts as directS-arylation sources in this type of chemical transformation.
- Li, Jianxiao,Tang, Hao,Lin, Zidong,Yang, Shaorong,Wu, Wanqing,Jiang, Huanfeng
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p. 4071 - 4078
(2020/06/09)
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- Synthesis of Polysubstituted 3-Chalcogenated Indoles through Copper(I) Iodide-Catalyzed Three-Component Domino Reactions
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Polysubstituted 3-chalcogenated indoles were synthesized by a three-component, one-pot, domino reaction of a N -(2-bromophenyl)trifluoroacetamide, a 1-alkyne, a disulfides or diselenides, CuI, and proline in DMF. In this process, tandem Sonogashira coupling, N-cyclization, and sulfenyl/selenyl electrophilic substitution occurred sequentially and smoothly to form the anticipated products in good to excellent yields (20 examples; 65-96%). Notably, no palladium catalyst was used in this catalytic system, supporting its cost effectiveness and potential industrial application.
- Gou, Rui,Zhang, Yi,Wu, Sheng-Wei,Liu, Feng
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supporting information
p. 207 - 212
(2019/01/14)
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- Metal Free Mono- and 2,3-Bis-sulfenylation of Indoles in Water with Sodium Sulfinates as a Sulfur Source
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An iodine-PPh3 mediated sulfenylation of indoles in water with stable and odorless sodium sulfinates as the sulfur source is described. The reaction could afford monosulfenylated indoles in moderate to excellent yields under metal free conditions. Moreover, double C—H sulfenylation of indoles at 2- and 3-positions has also been achieved by using excess sodium sulfinates under the optimized reaction conditions.
- Liu, Changqing,Fan, Jian,Wu, Manyi,Chen, Jiahui,Zhao, Yiming,Xie, Meihua
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p. 819 - 825
(2018/07/30)
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- Method for directly synthesizing indole by using nitrile
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The invention discloses a method for directly synthesizing indole by using nitrile. The method is characterized in that a 2-iodotoluene derivative is served as a substrate, anhydrous copper sulfate, potassium tert-butoxide, a cyanophenyl derivative and the 2-iodophene derivative are mixed according to the molar ratio of (0.02-0.1): (2-4): (5-20):1, reaction is carried out for 4-48 hours at 60-105DEG C in a solvent, petroleum ether/dichloromethane/ethyl acetate are mixed according to the volume ratio of (20-5):10:1 so as to be served as an eluent, and separation is carried out by using a silica gel column so as to obtain a target product. The method has the advantages that the operation is simple, the conditions are mild, the yield is high, and the method is a green and novel synthetic method.
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Paragraph 0047-0049
(2018/12/13)
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- NH4I-catalyzed chalcogen(S/Se)-functionalization of 5-membered N-heteroaryls under metal-free conditions
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Herein, we described the NH4I-catalyzed C–H bond chalcogenation of N-heteroaryls in the presence of a minimum amount of DMSO/H2O/acetic acid as additives (2.5/2.5/1 M equiv., respectively), under metal-free conditions. Under optimized conditions, a wide variety of sulfenyl/selenyl imidazo[1,2-α]pyridines were prepared in very good yields. Moreover, the present approach was also highly efficient for the chalcogenation of different 5-membered N-heteroaryls, e.g., indole, imidazothiazole, indazole and imidazopyrimidine derivatives.
- Bettanin, Luana,Saba, Sumbal,Doerner, Carlos V.,Franco, Marcelo S.,Godoi, Marcelo,Rafique, Jamal,Braga, Antonio L.
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p. 3971 - 3980
(2018/06/12)
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- Direct, Metal-free C(sp2)?H Chalcogenation of Indoles and Imidazopyridines with Dichalcogenides Catalysed by KIO3
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Herein, we report a greener protocol for the synthesis of 3-Se/S-indoles and imidazo[1,2-a]pyridines through direct C(sp2)?H bond chalcogenation of heteroarenes with half molar equivalents of different dichalcogenides, using KIO3 as a non-toxic, easy-to-handle catalyst and a stoichiometric amount of glycerol. The reaction features are high yields, based on atom economy, easy performance on gram-scale, metal- and solvent-free conditions as well as applicability to different types of N-heteroarenes.
- Rafique, Jamal,Saba, Sumbal,Franco, Marcelo S.,Bettanin, Luana,Schneider, Alex R.,Silva, Lais T.,Braga, Antonio L.
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supporting information
p. 4173 - 4180
(2018/02/06)
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- Visible-Light-Mediated Eosin Y Photoredox-Catalyzed Vicinal Thioamination of Alkynes: Radical Cascade Annulation Strategy for 2-Substituted-3-sulfenylindoles
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An organic dye photoredox-catalyzed regiospecific radical cascade annulation strategy of 2-alkynyl-azidoarenes to generate 3-sulfenylindoles via vicinal thioamination of alkynes at room temperature, mediated by visible light, was developed. The method req
- Tambe, Shrikant D.,Rohokale, Rajendra S.,Kshirsagar, Umesh A.
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supporting information
p. 2117 - 2121
(2018/05/31)
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- Microwave assisted metal-/oxidant-free cascade electrophilic sulfenylation/5-endo-dig cyclization of 2-alkynylanilines to generate diversified 3-sulfenylindoles
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A metal-/oxidant-free sustainable protocol for the synthesis of 3-sulfenylindoles based on electrophilic cyclization of 2-alkynylanilines has been developed under microwave irradiation. Herein, catalytic amount of iodine and stoichiometric amount of sulfonyl hydrazides were employed as catalyst and electrophiles respectively to induce the 5-endo-dig cyclization of 2-alkynylanilines. This strategy allows a wide substrate scope, demonstrates good functional group tolerance, utilizes easily available reagents and overcome multistep synthesis.
- Sharma, Shivani,Pathare, Ramdas S.,Sukanya,Maurya, Antim K.,Goswami, Bhagyashree,Agnihotri, Vijai K.,Sawant, Devesh M.,Pardasani, Ram T.
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supporting information
p. 3823 - 3826
(2017/09/15)
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- Palladium-catalyzed tandem addition/cyclization in aqueous medium: Synthesis of 2-arylindoles
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An efficient protocol to construct 2-arylindoles was developed through palladium-catalyzed tandem addition/cyclization of potassium aryltrifluoroborates with aliphatic nitriles in aqueous medium. The use of water as the reaction medium makes the synthesis process environmentally benign. A plausible mechanism for the formation of 2-arylindoles involving sequential nucleophilic addition followed by an intramolecular cyclization is proposed. Moreover, the utility of this catalytic tandem transformation was also demonstrated in an efficient gram-scale synthesis. This method provides an alternative synthetic tool for accessing a more diverse array of 2-arylindoles.
- Yu, Shuling,Hu, Kun,Gong, Julin,Qi, Linjun,Zhu, Jianghe,Zhang, Yetong,Cheng, Tianxing,Chen, Jiuxi
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p. 4300 - 4307
(2017/07/10)
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- Assembly of 3-Sulfenylbenzofurans and 3-Sulfenylindoles by Palladium-Catalyzed Cascade Annulation/Arylthiolation Reaction
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A novel and efficient palladium-catalyzed cascade annulation/arylthiolation reaction has been developed to afford functionalized 3-sulfenylbenzofuran and 3-sulfenylindole derivatives in moderate to good yields from readily available 2-alkynylphenols and 2
- Li, Jianxiao,Li, Chunsheng,Yang, Shaorong,An, Yanni,Wu, Wanqing,Jiang, Huanfeng
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p. 2875 - 2887
(2016/04/26)
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- Microwave-assisted synthesis of 3-sulfenylindoles by sulfonyl hydrazides using organic ionic base-Br?nsted acid
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A novel, efficient, and high-yielding method was developed for the synthesis of 3-sulfenylindoles via a DBU-based ionic liquid promoted sulfenylation of indoles using sulfonyl hydrazides as a thiol surrogate. The environmentally friendly procedure, easy operation and mild reaction conditions enable the tolerance of a wide scope of functionalities as well as high reaction efficiency. The synthetic procedure is suitable for both N-protected or unprotected indoles.
- Rahaman, Rajjakfur,Devi, Namita,Sarma, Kuladip,Barman, Pranjit
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p. 10873 - 10879
(2016/02/05)
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- Indium chloride: A versatile Lewis acid catalyst for the synthesis of 3-sulfenylindoles
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Indium chloride has been used as a versatile Lewis acid catalyst for the synthesis of 3-sulfenylindoles in good yields by the independent reaction of indoles and N-alkylindoles with N-(phenylthio)phthalimide in dimethyl formamide (DMF) at 100°C for about 5-6 h.
- Praveen Kumar,Dathu Reddy,Venkata Ramana Reddy,Rama Devi,Dubey
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p. 356 - 361
(2014/06/10)
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- Iodine-catalyzed regioselective sulfenylation of indoles with sulfonyl hydrazides
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New S in town: Sulfonyl hydrazides smoothly undergo sulfenylation with indoles in the presence of 10 mol % I2 to give structurally diverse indole thioethers in moderate to excellent yields with extremely high regioselectivity. This study paves the way for the use of sulfonyl hydrazides as unique sulfur electrophiles in chemical synthesis. Copyright
- Yang, Fu-Lai,Tian, Shi-Kai
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supporting information
p. 4929 - 4932
(2013/06/04)
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- Facile carbon-sulfur bond cleavage in diarylsulfonium ylides: A catalytic sulfur-to-silicon group transfer
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An unusual cleavage of the non-ylidic carbon-sulfur bond of a sulfonium ylide is reported. The reaction can be catalysed by a variety of palladium(ii) complexes under mild conditions. Preliminary results show that coordination of the ylide to the metal center results in significant structural changes.
- Huang, Xueliang,Goddard, Richard,Maulide, Nuno
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supporting information
p. 4292 - 4294
(2013/05/23)
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- K2CO3 promoted direct sulfenylation of indoles: A facile approach towards 3-sulfenylindoles
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An efficient and convenient method was developed for the preparation of 3-sulfenylindoles via a K2CO3 promoted direct sulfenylation of indoles with disulfides. The method is applicable to a wide range of indoles containing different
- Sang, Peng,Chen, Zhengkai,Zou, Jianwei,Zhang, Yuhong
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supporting information
p. 2096 - 2100
(2013/09/24)
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- Metal-free synthesis of 3-sulfenylindoles via an iodine-mediated electrophilic cyclisation of 2-alkynylanilines with disulfides
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An efficient and metal-free method was developed to synthesise 3-sulfenylindoles via the iodine-mediated electrophilic cyclisation of 2-alkynylanilines with disulfides. In the presence of I2, various 3-sulfenylindoles were obtained in moderate
- Tao, Li-Ming,Liu, Wen-Qi,Zhou, Yun,Li, Ai-Tao
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p. 644 - 646
(2013/02/22)
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- Venting-while-heating microwave-assisted synthesis of 3-arylthioindoles
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We report the first example of venting-while-heating microwave-assisted synthesis of a small library of 3-arylthioindoles. Compounds were prepared in excellent isolated yields (90-98%) within 4 min in a closed vessel by treating indoles with disulfides in the presence of sodium hydride in anhydrous N,N-dimethylformamide. The method was not affected by electron-donating and -withdrawing substituents both on 3-arylthio moiety and at 2- and 5-positions of the indole nucleus.
- La Regina, Giuseppe,Gatti, Valerio,Famiglini, Valeria,Piscitelli, Francesco,Silvestri, Romano
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scheme or table
p. 258 - 262
(2012/05/20)
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- A metal-free sulfenylation and bromosulfenylation of indoles: Controllable synthesis of 3-arylthioindoles and 2-bromo-3-arylthioindoles
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An efficient metal-free sulfenylation of indoles with disulfides has been developed, leading to 3-arylthioindoles in moderate to excellent yields. Furthermore, bromosulfenylation of indoles with disulfides has been realized for the first time providing a
- Huang, Dayun,Chen, Jiuxi,Dan, Weixing,Ding, Jinchang,Liu, Miaochang,Wu, Huayue
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p. 2123 - 2128
(2012/11/06)
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- Copper-catalyzed chalcogenoamination of 2-alkynylanilines with dichalcogenides for one-step synthesis of 3-sulfenylindoles and 3-selenylindoles
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The copper-catalyzed chalcogenoamination of 2-alkynylanilines with dichalcogenides has been achieved under mild reaction conditions using the weak base Cs2CO3 in combination with air oxidant, providing a convenient and efficient meth
- Li, Zhen,Hong, Longcheng,Liu, Ruiting,Shen, Jianzhong,Zhou, Xigeng
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scheme or table
p. 1343 - 1347
(2011/04/15)
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- Palladium-catalyzed annulation of 2-(1-Alkynyl)benzenamines with disulfides: Synthesis of 3-sulfenylindoles
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3-Sulfenylindoles can be efficiently prepared in moderate to good yields from 2-(1-alkynyl)benzenamines and disulfides using the palladium/air catalytic systems. The study also provides a useful route to the synthesis of fipronil analogues.
- Guo, Yan-Jin,Tang, Ri-Yuan,Li, Jin-Heng,Zhong, Ping,Zhang, Xing-Guo
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scheme or table
p. 2615 - 2618
(2009/12/29)
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- Simple indole synthesis by one-pot sonogashira coupling-NaOH-mediated cyclization
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Coupling of o-iodoanilines with terminal alkynes under standard Sonogashira conditions, and further treatment with NaOH under conventional heating or microwave irradiation, afford 2-substituted indoles in usually high yields. Functionalities such as halides, nitro, and cyano groups are tolerated under the reaction conditions. Georg Thieme Verlag Stuttgart.
- Sanz, Roberto,Guilarte, Verónica,Castroviejo, M. Pilar
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experimental part
p. 3006 - 3010
(2009/07/03)
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- Vanadium-catalyzed sulfenylation of indoles and 2-naphthols with thiols under molecular oxygen
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Vanadium oxyacetylacetonate [VO(acac)2] works as a catalyst for the direct synthesis of 3-sulfanylindoles from indoles and thiols under an atmospheric pressure of molecular oxygen as a reoxidant. For example, the reaction of 2-phenylindole with benzenethiol in the presence of a catalytic amount of VO(acac)2, potassium iodide, and 2,6-di-tert-butyl-p-cresol in chlorobenzene under molecular oxygen proceeds to afford 2-phenyl-3- (phenylsulfanyl)indole in 86% yield. This catalytic system can also be applied to 2-naphthols instead of indoles to give the corresponding 1-sulfanyl-2- naphthols in up to 57% yield.
- Maeda, Yasunari,Koyabu, Motonori,Nishimura, Takahiro,Uemura, Sakae
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p. 7688 - 7693
(2007/10/03)
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- Facile and efficient sulfenylation method using quinone mono-O,S-acetals under mild conditions
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A novel sulfenylation method induced by aromatization of quinone mono-O,S-acetals is described. These sulfenylation reagents readily react with silyl enolethers or electron rich aromatic compounds to give sulfenylation products under mild conditions. In particular, O,S-acetal 2j, which possesses a pentafluorophenylthio function, is the most effective reagent from the standpoint of the adaptability for various substrates.
- Matsugi,Murata,Gotanda,Nambu,Anilkumar,Matsumoto,Kita
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p. 2434 - 2441
(2007/10/03)
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- A study of vinyl radical cyclization onto the azido group by addition of sulfanyl, stannyl, and silyl radicals to alkynyl azides
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Thermal radical reactions of azidoalkynes 2, 8, 14, and 21a-c with thiols 1a-c afford 2-sulfanylvinyl radicals by selective addition of sulfanyl radicals to the triple bond. 1-Phenylvinyl radicals 23 and 30a, as well as vinyl radical 30b, undergo fast 5-cyclization onto the aromatic azide function to give cyclized indoles. In contrast, both 1-phenyl (15, 17) and 1-alkyl (3a,b, 9) vinyl radicals fail to add to their aliphatic azido substituents and exclusively undergo cyclization onto the aromatic sulfanyl ring and H transfer from the thiol precursor. Azidoalkynes 14 and 21a react with Bu3SnH and TMSS under radical conditions to give instead the corresponding amines as a result of preferential attack of Bu3Sn · and (TMS)3Si · radicals on the azido group rather than on the triple bond. Evidence is provided that alkyl radical cyclizations onto azides are not feasible in the presence of thiol, in contrast with the reported utility of these cyclization reactions in the presence of Bu3SnH and TMSS.
- Montevecchi, Pier Carlo,Navacchia, Maria Luisa,Spagnolo, Piero
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p. 1219 - 1226
(2007/10/03)
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- A novel efficient sulfenylation method using quinone mono-O,S-acetals under mild conditions
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A novel method for sulfenylation induced by aromatization of quinone mono-O,S-acetals is described.
- Matsugi, Masato,Gotanda, Kentoku,Murata, Kenji,Kita, Yasuyuki
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p. 1387 - 1388
(2007/10/03)
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- ELECTRON-TRANSFER PROCESSES: SULPHENYLATION OF ELECTRON-RICH SYSTEMS BY DIARYL DISULPHIDES AND ARYLTHIOSULPHONATES
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Diphenyl disulphide, 1, reacts with 1-methyl-2-phenylindolizine, 2, in refluxing ethanol furnishing sulphenylation; dibenzothiazolyl disulphide, 6, a compound with a low S-S bond energy reacts with the isomers 1-methyl-2-phenylindolizine, 2, and 3-methyl-2-phenylindolizine, 3, at room temperature in high yields. 2-Phenylindole, 4, 1-methyl-2-phenylindole, 5, and some of their 3-substituted derivatives, which have an higher oxidation potential than indolizines, react with diphenyl disulphide only under irradiation.The sulphenylation of these substrates can be easily obtained either by metal activation or using dibenzothiazolyl disulphide, 6.Arylthiosulphonates sulphenylate indole and indolizine derivatives at room temperature.On the basis of reaction products and ESR evidence, all these reactions are discussed in terms of electron-transfer processes.
- Berti, Corrado,Colonna, Martino,Poloni, Marino
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p. 181 - 184
(2007/10/02)
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