- Palladium-Catalyzed Synthesis of Tricyclic Indoles via a N-S Bond Cleavage Strategy
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In palladium/norbornene (Pd/NBE) chemistry, the "ortho effect"has been proven to be a key factor in the process of β-carbon elimination to extrude NBE. Herein, we found that the o-iodoaniline protected by a p-methoxybenzenesulfonyl group can recover the "
- Zhang, Bo-Sheng,Wang, Fan,Gou, Xue-Ya,Yang, Ying-Hui,Jia, Wan-Yuan,Liang, Yong-Min,Wang, Xi-Cun,Li, Yuke,Quan, Zheng-Jun
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supporting information
p. 7518 - 7523
(2021/10/01)
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- Modification of the 4-phenylbutyl side chain of potent 3-benzazepine-based GluN2B receptor antagonists
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Excitotoxicity driven by overactivation of NMDA receptors represents a major mechanism of acute and chronic neurological and neurodegenerative disorders. Negative allosteric modulators interacting with the ifenprodil binding site of the NMDA receptor are able to interrupt this ongoing neurodamaging process. Starting from the potent 3-benzazepine-1,7-diol 4a novel NMDA receptor antagonists were designed by modification of the N-(4-phenylbutyl) side chain. With respect to developing novel fluorinated PET tracers, regioisomeric fluoroethoxy derivatives 11, 12, 14, and 15 were synthesized. Analogs 19 and 20 with various heteroaryl moieties at the end of the N-side chain were prepared by Sonogashira reaction and nucleophilic substitution. The fluoroethyl triazole 37 was obtained by 1,3-dipolar cycloaddition. In several new ligands, the flexibility of the (hetero)arylbutyl side chain was restricted by incorporation of a triple bond. The affinity towards the ifenprodil binding site was tested in an established competition assay using [3H]ifenprodil as radioligand. Introduction of a fluoroethoxy moiety at the terminal phenyl ring, replacement of the terminal phenyl ring by a heteroaryl ring and incorporation of a triple bond into the butyl spacer led to considerable reduction of GluN2B affinity. The phenol 15 (Ki = 193 nM) bearing a p-fluoroethoxy moiety at the terminal phenyl ring represents the most promising GluN2B ligand of this series of compounds. With exception of 15 showing moderate σ2 affinity (Ki = 79 nM), the interaction of synthesized 3-benzazepines towards the PCP binding site of the NMDA receptor, σ1 and σ2 receptors was rather low (Ki > 100 nM).
- Wagner, Marina,Schepmann, Dirk,Ametamey, Simon M.,Wünsch, Bernhard
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supporting information
p. 3559 - 3567
(2019/07/03)
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- External Oxidant-Free Oxidative Tandem Cyclization: NaI-Catalyzed Thiolation for the Synthesis of 3-Thiosubstituted Pyrroles
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A simple method for the synthesis of 3-thiosubstituted pyrroles from homopropargylic amines and thiosulfonates via a tandem sulfenylation/cyclization has been developed. The thiosulfonates are used both as substrates and oxidants in this transformation. This procedure exhibits good functional group tolerance and a series of 3-thiosubstituted pyrrole derivatives was obtained in moderate to good yields. (Figure presented.).
- Yuan, Bingxiang,Jiang, Yong,Qi, Zhenjie,Guan, Xin,Wang, Ting,Yan, Rulong
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supporting information
p. 5112 - 5117
(2019/11/11)
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- Tert-Butyl Nitrite Promoted Oxidative Intermolecular Sulfonamination of Alkynes to Synthesize Substituted Sulfonyl Pyrroles from the Alkynylamines and Sulfinic Acids
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tert-Butyl nitrite promoted oxidative intermolecular sulfonamination of alkynes to synthesize substituted sulfonyl pyrroles from the alkynylamines and sulfinic acids via tandem addition/cyclization was developed. This reaction is performed well by employing tert-butyl nitrite as the oxidant, and various substituted sulfonyl pyrroles are formed in moderate to good yields with no requirement of metal catalysis.
- Qi, Zhenjie,Jiang, Yong,Wang, Yanyan,Yan, Rulong
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supporting information
p. 8636 - 8644
(2018/06/18)
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- Cu-Catalyzed Tandem Aerobic Oxidative Cyclization for the Synthesis of 3,3′-Bipyrroles from the Homopropargylic Amines
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A Cu-catalyzed method for the synthesis of 3,3′-bipyrroles from homopropargylic amines through tandem aerobic oxidative cyclization involving the formation of C-C bond has been developed. The features of this reaction are a small number of Cu catalysis and simple starting substrates. Moreover, this procedure exhibits good functional group tolerance and a series of 3,3′-bipyrroles derivatives are obtained in moderate to good yields.
- Qi, Zhenjie,Jiang, Yong,Yuan, Bingxiang,Niu, Yanning,Yan, Rulong
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supporting information
p. 5048 - 5052
(2018/08/24)
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- Regioselective Amine–Borane Cyclization: Towards the Synthesis of 1,2-BN-3-Cyclohexene by Copper-Assisted Triazole/Gold Catalysis
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The combination of triazole/gold (TA-Au) and Cu(OTf)2is identified as the optimal catalytic system for promoting intramolecular hydroboration for the synthesis of a six-membered cyclic amine–borane. Excellent yields (up to 95 %) and regioselectivities (5-exo vs. 6-endo) were achieved through catalyst control and sequential dilution. Good functional-group tolerance was attained, thus allowing the preparation of highly functionalized cyclic amine–borane substrates, which could not be achieved using other methods. Deuterium-labeling studies support the involvement of a hydride addition to a gold-activated alkyne with subsequent C?B bond formation.
- Motika, Stephen E.,Wang, Qiaoyi,Akhmedov, Novruz G.,Wojtas, Lukasz,Shi, Xiaodong
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supporting information
p. 11582 - 11586
(2016/10/24)
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- Palladium(II)-Catalyzed Regioselective syn-Hydroarylation of Disubstituted Alkynes Using a Removable Directing Group
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A palladium(II)-catalyzed regioselective syn-hydroarylation reaction of homopropargyl amines has been developed, wherein selectivity is controlled by a cleavable bidentate directing group. Under the optimized reaction conditions, both dialkyl and alkylaryl alkyne substrates were found to undergo hydroarylation with high selectivity. The products of this reaction contain a 4,4-disubstituted homoallylic amine motif that is commonly seen in drug molecules and other bioactive compounds.
- Liu, Zhen,Derosa, Joseph,Engle, Keary M.
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supporting information
p. 13076 - 13081
(2016/10/13)
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- Scope and limitations of a DMF bio-alternative within Sonogashira cross-coupling and Cacchi-type annulation
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Pd-catalysed C-C bond formation is an essential tool within the pharmaceutical and agrochemical industries. Many of these reactions rely heavily on polar aprotic solvents; however, despite their utility, these solvents are incompatible with the drive towards more sustainable chemical synthesis. Herein, we describe the scope and limitations of an alternative to DMF derived from renewable sources (Cyrene) in Sonogashira cross-coupling and Cacchi-type annulations.
- Wilson, Kirsty L.,Kennedy, Alan R.,Murray, Jane,Greatrex, Ben,Jamieson, Craig,Watson, Allan J. B.
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supporting information
p. 2005 - 2011
(2016/10/05)
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- Cu-catalyzed arylcarbocyclization of alkynes with diaryliodonium salts through C-c bond formation on inert C(sp3)-H bond
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Copper-catalyzed arylcarbocyclization reaction of alkynes was realized with diaryliodonium salts through C-C bond formation on an inert C(sp3)-H bond. This method provides an efficient cyclization of alkyl alkynes to generate carbocycles with good step-economy. Theoretical study revealed an interesting Cu-catalyzed concerted pathway of the C-C bond formation.
- Peng, Jing,Chen, Chao,Chen, Junjie,Su, Xiang,Xi, Chanjuan,Chen, Hui
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supporting information
p. 3776 - 3779
(2014/08/05)
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- Fused ring aziridines as a facile entry into triazole fused tricyclic and bicyclic heterocycles
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The intramolecular dipolar cycloaddition of an azide with an alkyne has provided a useful entry into triazole fused tricyclic heterocycles containing both the triazole ring and the oxazolidin-2-one ring system. The requisite azido-alkynes have been prepared via a two-step sequence from fused ring aziridines. A series of 6-12 membered rings containing both the oxazolidinone and triazole rings have been prepared. These ring systems have been designed as conformationally restrained analogs of RNA-binding oxazolidinones. The Royal Society of Chemistry 2012.
- Fang, Fang,Vogel, Megan,Hines, Jennifer V.,Bergmeier, Stephen C.
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scheme or table
p. 3080 - 3091
(2012/05/07)
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- Au(I)/Au(III)-catalyzed Sonogashira-type reactions of functionalized terminal alkynes with arylboronic acids under mild conditions
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A straightforward, efficient, and reliable redox catalyst system for the Au(I)/Au(III)-catalyzed Sonogashira cross-coupling reaction of functionalized terminal alkynes with arylboronic acids under mild conditions has been developed.
- Qian, Deyun,Zhang, Junliang
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supporting information; experimental part
p. 808 - 812
(2011/08/10)
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- Et2Zn-catalyzed intramolecular hydroamination of alkynyl sulfonamides and the related tandem cyclization/addition reaction
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(Chemical Equation Presented) Intramolecular hydroamination of alkynyl amides was effected by a catalytic amount of Et2Zn (20 mol %) to form indole derivatives, and a tandem cyclization/nucleophilic addition procedure involving reaction of the indole zinc salt intermediate with acid chlorides or halides was developed to provide an efficient approach to C3-substituted indole derivatives when an excess of Et2Zn (120 mol %) was used.
- Yin, Yan,Ma, Wenying,Chai, Zhuo,Zhao, Gang
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p. 5731 - 5736
(2008/02/09)
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- Heterocyclic compounds useful as NMDA receptor selective subtype blockers
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The invention relates to compounds of formula wherein Ar1 is pyridyl or phenyl, substituted by hydroxy, lower alkyl, halogen, amino, nitro, benzyloxy or lower alkoxy-lower alkoxy, or is the group wherein Z1 is a five membered heteroc
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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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- Palladium-Catalyzed Intramolecular Addition of Amines to Acetylenes. Synthesis of Cyclic Imines
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Intramolecular aminopalladation of alkynylamines gave intermediary alkenylpalladium compounds that hydrolyzed and isomerized to thermodynamically stable cyclic imines.Treatment of 3-alkynylamines with a catalytic amount of PdCl2(MeCN)2 gave exclusively 1-
- Fukuda, Yukitoshi,Matsubara, Seijiro,Utimoto, Kiitiro
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p. 5812 - 5816
(2007/10/02)
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- Intramolecular N-(Acyloxy)iminium Ion-Alkyne Cycloadditions. A New Route to Bicyclic α-Amino Ketones
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The intramolecular cyclocondensation of 15 cyclic N-(acyloxy)iminium cations containing tethered alkyne and alkene nucleophiles is reported (eqs 5 and 6).This route to heterotricyclic systems was specifically demonstrated with substrates in which the hete
- Fisher, Matthew J.,Overman, Larry E.
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p. 1447 - 1459
(2007/10/02)
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- Vinyl Cations. 41. Influence of 4-Aryl and 4-Alkyl Substituents on the ?-Route Solvolyses of Homopropargyl Esters
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The four 4-substituted-homopropargyl tosylates and triflates 6b-e (R=phenyl, p-tolyl, anisyl, and cyclopropyl) have been synthesized and solvolyzed under various conditions, as have 2-cyclopropyl-1-cyclobutenyl triflate (11-OTf) and nonaflate (11-ONf).In addition, the solvolyses of pent-3-yn-1-yl tosylate (6a-OTs, R=methyl) and triflate (prepared previously) are reported.The ratios of C-3 ring to C-4 ring 3 ring/C4ring)> products are recorded for the reactions in various solvents.As expected, ring closure (kΔ) increases and solvent displacement (kS, SN2) decreases with decreasing nucleophilicity of solvent.Temperature effects are noted for the sovolyses of tosylates 6a-e in 100percent TFE buffered with Na2CO3 in which kΔ increases with increasing temperature.The result is explained by decomposition of the intimate ion pair with temperature, whereupon elimination to the enyne becomes smaller and ring closure (kΔ) increases at the expense of elimination.The possibility of intervention of nonclassical vinyl cations is discussed, as are other mechanistic implications.
- Collins, Clair J.,Hanack, Michael,Stutz, Herbert,Auchter, Gerhard,Schoberth, Winfried
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p. 5260 - 5268
(2007/10/02)
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