- 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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- 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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supporting information
p. 5860 - 5865
(2018/05/14)
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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; 0095; 0096
(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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- Regioselective Synthesis of Polyheterohalogenated Naphthalenes via the Benzannulation of Haloalkynes
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Independent control of halide substitution at six of the seven naphthalene positions of 2-arylnaphthalenes is achieved through the regioselective benzannulation of chloro-, bromo-, and iodoalkynes. The modularity of this approach is demonstrated through the preparation of 44 polyheterohalogenated naphthalene products, most of which are difficult to access through known naphthalene syntheses. The outstanding regioselectivity of the reaction is both predictable and proven unambiguously by single-crystal X-ray diffraction for many examples. This synthetic method enables the rapid preparation of complex aromatic systems poised for further derivatization using established cross-coupling methods. The power and versatility of this approach makes substituted naphthalenes highly attractive building blocks for new organic materials and diversity-oriented synthesis.
- Lehnherr, Dan,Alzola, Joaquin M.,Lobkovsky, Emil B.,Dichtel, William R.
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supporting information
p. 18122 - 18127
(2015/12/24)
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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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- 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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