- Method for preparing 1-halogenated alkyne under catalysis of heterogeneous Ag catalyst at room temperature
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The invention discloses a novel method for preparing 1-halogenated alkyne under the catalysis of a heterogeneous Ag catalyst at room temperature. The method comprises the steps of mixing terminal alkyne compounds containing different substituent groups, N
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Paragraph 0023-0036; 0041
(2021/05/12)
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- Iron-Catalyzed Cross-Coupling of Alkynyl and Styrenyl Chlorides with Alkyl Grignard Reagents in Batch and Flow
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Transition-metal-catalyzed cross-coupling chemistry can be regarded as one of the most powerful protocols to construct carbon–carbon bonds. While the field is still dominated by palladium catalysis, there is an increasing interest to develop protocols that utilize cheaper and more sustainable metal sources. Herein, we report a selective, practical, and fast iron-based cross-coupling reaction that enables the formation of Csp?Csp3 and Csp2?Csp3 bonds. In a telescoped flow process, the reaction can be combined with the Grignard reagent synthesis. Moreover, flow allows the use of a supporting ligand to be avoided without eroding the reaction selectivity.
- Deng, Yuchao,Wei, Xiao-Jing,Wang, Xiao,Sun, Yuhan,No?l, Timothy
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supporting information
p. 14532 - 14535
(2019/11/21)
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- Transition-Metal-Free One-Step Synthesis of Ynamides
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A robust transition-metal-free one-step strategy for the synthesis of ynamides from sulfonamides and (Z)-1,2-dichloroalkenes or alkynyl chlorides is presented. This method is not only effective for internal ynamides but also amenable for terminal ynamides. Various functional groups, even the vinyl moiety, are compatible, and thus, this strategy offers the opportunity for further functionalization.
- Zeng, Xianzhu,Tu, Yongliang,Zhang, Zhenming,You, Changming,Wu, Jiao,Ye, Zhiying,Zhao, Junfeng
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p. 4458 - 4466
(2019/03/26)
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- Gold-Catalyzed Highly Chemo- and Regioselective C-H Bond Functionalization of Phenols with Haloalkynes
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A highly chemo- and stereoselective addition of unprotected phenols to haloalkynes was developed. A ligand and counterion controlled process enabled the highly site-selective and chemoselective C-H bond functionalization of phenol derivatives with haloalkynes in moderate to excellent yield at room temperature. The simple availability of the starting materials in combination with the preferred para-C-H functionalization over a competing O-H insertion makes this an attractive protocol. The stereoselectivity of the products depends on the choice of the catalyst. From a synthetic prospective, this method offers an efficient route towards vinyl chlorides, which are valuable precursors for the synthesis of pharmaceutical drugs.
- Adak, Tapas,Schulmeister, Jürgen,Dietl, Martin C.,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 3867 - 3876
(2019/06/25)
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- Palladium-Catalyzed Decarboxylative γ-Arylation for the Synthesis of Tetrasubstituted Chiral Allenes
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An enantiospecific palladium-catalyzed decarboxylative coupling of acyclic β,γ-alkynoic acids with various aryl iodides to chiral tetrasubstituted allenes is described. The coupling reaction comprises a decarboxylative γ-palladation of α,α-disubstituted carboxylic acids to provide the tetrasubstituted allenes with complete point-to-axial chirality transfer in excellent yields.
- Scheipers, Ina,Mück-Lichtenfeld, Christian,Studer, Armido
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supporting information
p. 6545 - 6548
(2019/04/17)
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- Au-Catalyzed Intermolecular [2+2] Cycloadditions between Chloroalkynes and Unactivated Alkenes
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The [2+2] cycloaddition is a versatile strategy for the synthesis of strained cyclobutenes of high synthetic value. In this study, two efficient intermolecular [2+2] cycloadditions between two different types of chloroalkynes and unactivated alkene are realized with gold catalysis. Of significance is that the reaction works with challenging monosubstituted unactivated alkenes, which is unprecedented in gold catalysis and scarcely documented in other metal-catalyzed/promoted reactions; moreover, the reaction exhibits excellent regioselectivities, which are much better than those reported in literature. With 1,2-disubstituted unactivated alkenes, the reaction is largely stereospecific. The cyclobutene products can be prepared in nearly gram scale and readily undergo further reactions including various cross-coupling reactions using the C(sp2)-Cl and/or C(sp2)-SPh bond, which in turn substantially broaden the scope of accessible cyclobutenes and enhance the synthetic utility of this bimolecular reaction.
- Bai, Yu-Bin,Luo, Zaigang,Wang, Yuguang,Gao, Jin-Ming,Zhang, Liming
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p. 5860 - 5865
(2018/05/14)
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- Manganese-Catalyzed Dual-Deoxygenative Coupling of Primary Alcohols with 2-Arylethanols
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Reported herein is a general and efficient dual-deoxygenative coupling of primary alcohols with 2-arylethanols catalyzed by a well-defined Mn/PNP pincer complex. This reaction is the first example of the catalytic dual-deoxygenation of alcohols using a non-noble-metal catalyst. Both deoxygenative homocoupling of 2-arylethanols (17 examples) and their deoxygenative cross-coupling with other primary alcohols (20 examples) proceeded smoothly to form the corresponding alkenes by a dehydrogenation and deformylation reaction sequence.
- Wang, Yujie,Shao, Zhihui,Zhang, Kun,Liu, Qiang
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supporting information
p. 15143 - 15147
(2018/11/01)
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- Highly efficient and recyclable catalyst for the direct chlorination, bromination and iodination of terminal alkynes
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Direct halogenation, including chlorination, bromination and iodination of terminal alkynes, are of great importance in organic synthesis. Here an efficient and recyclable nano-Ag/g-C3N4 catalyst system was developed and proved to be remarkably active with 39 examples varied from chlorination, bromination to iodination, of which 14 runs have yielded more than 95% of the product. Recycling of the catalyst was also achieved without obvious activity loss after several runs: 99% yield was observed even after 5 runs in the bromination of phenylacetylene. The catalysts system is of low cost and easy to be prepared, making this procedure versatile, convenient and economic.
- Shi, Wei,Guan, Zhipeng,Cai, Peng,Chen, Hao
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p. 199 - 204
(2017/08/10)
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- A copper (II) (II) composite chlorinating agent and copper-based composite chlorinating agent synthesis of 1-chloro-2-aryl acetylene method
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The invention discloses a copper (II) composite chlorinating agent and a method for synthesizing 1-chlorine-2-aryl acetylene based on the copper (II) composite chlorinating agent. The structural formula of the copper (II) composite chlorinating agent is CuCl2.xNaCl.yAl2O3. The chlorinating agent is applicable to chlorination of various substituted aryl acetylene substrates, and is high in universality; the chlorinating agent can directly carry out chlorination reaction on aryl acetylene so as to obtain a 1-chlorine-2-aryl acetylene product; the method is mild in reaction condition, 1-chlorine-2-aryl acetylene can be synthesized with high yield and high selectivity, and the production cost of the 1-chlorine-2-aryl acetylene derivative is greatly lowered.
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Paragraph 0028; 0080; 0084
(2016/11/24)
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- Silver-catalyzed synthesis of 1-chloroalkynes directly from terminal alkynes
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An efficient method to prepare 1-chloroalkynes was investigated. The method involved the use of readily available terminal alkynes and a catalytic amount of a silver salt with N-chlorosuccinimide as the chlorinating agent under mild conditions. Compared with the existing process, this method has a broad substrate scope: 19 examples were explored, and the products were obtained in excellent yields and were easily isolated by vacuum distillation. Moreover, recycling of the catalyst was achieved by simple filtration and desiccation, which made the method more economic and environmentally benign.
- Shi, Dunfa,Liu, Zhiwen,Zhang, Ziyu,Shi, Wei,Chen, Hao
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p. 1424 - 1426
(2015/06/10)
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- An improved transition-metal-free synthesis of aryl alkynyl sulfides via substitution of a halide at an sp-centre
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A simple high-yielding preparation of aryl alkynyl sulfides is presented. The reaction of a chloroacetylene with a thiolate salt in the presence of an amine mediator (dimethylamine or N,N′-dimethylethylenediamine) yields the alkynyl sulfides in excellent yields. The alkynyl chloride is easily prepared from the parent alkyne.
- Chowdhury, Roomi Mohima,Wilden, Jonathan D.
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supporting information
p. 5859 - 5861
(2015/06/02)
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- A versatile and highly efficient method for 1-chlorination of terminal and trialkylsilyl-protected alkynes
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A highly efficient one-pot procedure for the preparation of 1-chloroalkynes and 1-chlorobutadiynes from terminal and trialkylsilyl-protected precursors is reported. This convenient reaction, proceeding under mild conditions, utilizes N-chlorosuccinimide as the chlorinating agent and tolerates a range of functional groups. A general chlorination of alkynes: A highly efficient one-pot procedure for the preparation of 1-chloroalkynes and 1-chlorobutadiynes from terminal and trialkylsilyl-protected precursors is reported (see figure; TMS=trimethylsilyl, TES=triethylsilyl, TBDMS=tert-butyldimethylsilyl, TIPS=triisopropylsilyl). This convenient reaction, proceeding under mild conditions, utilizes N-chlorosuccinimide as the chlorinating agent and tolerates a range of functional groups.
- Gulia, Nurbey,Pigulski, Bartlomiej,Charewicz, Marta,Szafert, Slawomir
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supporting information
p. 2746 - 2749
(2014/03/21)
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- Facile and efficient synthesis of 1-haloalkynes via DBU-mediated reaction of terminal alkynes and N-haloimides under mild conditions
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Directly from terminal alkynes and with N-halosuccinimides (halo = Br and I) or N-cholorophthalimide as the halogen sources, DBU as the activator, 1-haloalkynes were prepared in good to excellent yields at room temperature. Bis(bromoalkyne) and bis(iodoal
- Li, Mengru,Li, Yueju,Zhao, Baozhong,Liang, Fushun,Jin, Long-Yi
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p. 30046 - 30049
(2014/08/05)
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- Synthesis of 1-chloroalkynes from alkynylsilanes using trichloroisocyanuric acid as chlorinating agent
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A new method is reported for preparing 1-chloroalkynes from alkynylsilanes using trichloroisocyanuric acid (TCCA) as chlorinating agent and AgNO 3 for in situ desilylation. The method is selective for trimethylsilyl-protected alkynes relative t
- Vilhelmsen, Mie Hojer,Andersson, Asbjorn Sune,Nielsen, Mogens Brondsted
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scheme or table
p. 1469 - 1472
(2009/12/10)
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- Analysis of substituent effects on C-13 NMR parameters of substituted arylacetylene derivatives. Linear free energy relationships and PM3 semiempirical calculations
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The substituent-induced chemical shifts (SCS) of C(α,β) on the 13C NMR spectra of arylalkynes (i.e. containing H, CH3, Cl and Br) were studied. The correlation between SCS and Hammett constants shows that the tendency of the effect by the substituents on the phenyl ring is Br (ρ=8.15)>Cl (ρ=7.27)>CH3 (ρ=6.79)>H (ρ=5.78). This order can be rationalized as due to the ability of the group on the alkyne to stabilize the partial positive charge on C(β) resulting from polarization with π electron transfer from C(β) to the phenyl ring. The SCS values are also well correlated with the electron densities obtained from PM3 calculations. The solvent effect on the 13C chemical shifts of phenylalkynyl bromide demonstrates a strong dependence on the relative permittivity as well as the shielding character of the solvents. (C) 2000 Elsevier Science Ltd.
- Lin, Shaw-Tao,Lee, Chuan-Chen,Liang, David W.
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p. 9619 - 9623
(2007/10/03)
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- An improved synthesis of dichloroalkylphosphonates, chloroalkynes and terminal alkynes via diethyl dichloromethylphosphonate
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Diethyl 1,1-dichloromethylphosphonate (2) was synthesised in good yield from the reduction of 1,1,1-trichloromethylphosphonate (1) with i-C3H7MgCl and subsequent hydrolysis. The reactivity of 2 towards α-alkylation and its utility in the synthesis of chloroalkynes and terminal alkynes was investigated.
- Carran, John,Waschbuesch, Rachel,Marinetti, Angela,Savignac, Philippe
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p. 1494 - 1498
(2007/10/03)
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- Attempts to Prepare an Alkynyldiazonium Salt
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The 2-bromo-1-chloroalkanal p-tosylhydrazones 11a and b react with triethylamine as base to give the azoalkenes 12, of which (1-chloro-2-phenylethenyl)tosyldiazene (12b) is obtained as a crystalline material at room temperature. 12b reacts with SbCl5 at -30 and -70 deg C to form different diazonium salts, which are treated with nucleophiles such as methanol and water.The products obtained (Schemes 3 and 4) indicate the formation of the phenylethenyldiazonium salt 20, which is stable up to -20 deg C. 20 adds nucleophiles like methanol or water as well as anisole at the CC triple bond before releasing nitrogen.
- Helwig, Reinhard,Hanack, Michael
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p. 1008 - 1021
(2007/10/02)
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- REACTION DE L'ACIDE PERCHLORIQUE SUR LES PHENYLACETYLENES SUBSTITUES. MISE EN EVIDENCE D'UN MECANISME IONIQUE ET RADICALAIRE
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We have studied the reaction of perchloric acid in acetic acid medium on some substituted phenylacetylenes.The ionic and radicalar mechanism is in agreement with the formation of and alkenyl perchlorate which is decomposed according to an homolytic process.
- Montheard, Jean-Pierre,Camps, Marcel,Benzaid, Ahmed,Pascal, Jean-Louis
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p. 3483 - 3486
(2007/10/02)
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