- Triple Mode of Alkylation with Ethyl Bromodifluoroacetate: N, or O-Difluoromethylation, N-Ethylation and S-(ethoxycarbonyl)difluoromethylation
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In this report, we have explored a triple mode of chemical reactivity of ethyl bromodifluoroacetate. Typically, bromodifluoroacetic acid has been used as a difluorocarbene precursor for difluoromethylation of soft nucleophiles. Here we have disclosed nucleophilicity and base dependent divergent chemical reactivity of ethyl bromodifluoroacetate. It furnishes lithium hydroxide and cesium carbonate promoted difluoromethylation of tosyl-protected aniline and electron-deficient phenols respectively. Interestingly, switching the base from lithium hydroxide to 4-N,N-dimethylamino pyridine (DMAP) tosyl-protected anilines afforded the corresponding N-ethylation product. Whereas, highly nucleophilic thiophenols furnished the corresponding S-carboethoxydifluoromethylation product via a rapid SN2 attack to the bromine atom prior to the ester hydrolysis. This mechanistic divergence was established through several control experiments. It was revealed that difluoromethylation reaction proceeds through a tandem in situ ester hydrolysis/decarboxylative-debrominative difluorocarbene formation and subsequent trapping by the soft nucleophile-NHTs or electron-deficient phenolic ?OH groups. In the presence of DMAP the hydrolysis of the ester is perturbed instead a nucleophilic attack at the ethyl moiety provides the N-ethylation product. Hence, besides the development of a practical base-promoted N-difluoromethylation of amines and electron-deficient phenols, divergent reactivity pattern of inexpensive and user-friendly ethyl bromodifluoroacetate has been explored. (Figure presented.).
- Polley, Arghya,Bairy, Gurupada,Das, Pritha,Jana, Ranjan
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supporting information
p. 4161 - 4167
(2018/09/21)
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- Visible-Light Photoredox-Catalyzed Aminosulfonylation of Diaryliodonium Salts with Sulfur Dioxide and Hydrazines
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A photoredox-catalyzed three-component synthesis of N-aminosulfonamides starting from diaryliodonium salts, hydrazines and sulfur dioxide is reported. This reaction proceeds under mild conditions at room temperature and is driven by visible light. A simple bisulfite salt can be used as a readily available and easy-to-handle sulfur dioxide source. Mechanistic studies support a catalytic photoredox pathway with the diaryliodonium salt as convenient source for aryl radicals. (Figure presented.).
- Liu, Nai-Wei,Liang, Shuai,Manolikakes, Georg
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supporting information
p. 1308 - 1319
(2017/04/18)
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- A Convenient Multigram Synthesis of DABSO Using Sodium Sulfite as SO2 Source
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A convenient synthesis of DABCO·(SO2)2 (abbreviated as DABSO) is reported. Using a two-chamber setup, sulfur dioxide is generated in one chamber and consumed in the other. This closed system overcomes safety issues related to working
- Van Mileghem, Seger,De Borggraeve, Wim M.
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supporting information
p. 785 - 787
(2017/05/29)
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- A copper-catalyzed three-component reaction of triethoxysilanes, sulfur dioxide, and hydrazines
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A three-component reaction of triethoxysilanes, sulfur dioxide, and hydrazines catalyzed by copper(II) acetate is reported, leading to N-aminosulfonamides in good yields. Not only triethoxy(aryl)silanes but also triethoxy(alkyl)silanes are compatible during the process of insertion of sulfur dioxide. Additionally, diethoxydiarylsilanes are suitable under the conditions as well.
- Wang, Xianbo,Xue, Lijun,Wang, Zhiyong
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supporting information
p. 4056 - 4058
(2014/08/18)
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- Catalytic conversion of aryl triazenes into aryl sulfonamides using sulfur dioxide as the sulfonyl source
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Various sulfonamides have been synthesized from triazenes and sulfur dioxide. In the presence of just a catalytic amount of BF3· OEt2, a series of 1-aryl-triazenes were converted into sulfonyl hydrazines in good to excellent yields. When using CuCl2 as the catalyst, the corresponding sulfonamides can be produced from the 1-aryl triazenes in good yields. This journal is the Partner Organisations 2014.
- Li, Wanfang,Beller, Matthias,Wu, Xiao-Feng
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supporting information
p. 9513 - 9516
(2014/08/18)
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- Aminosulfonylation of aromatic amines, sulfur dioxide and hydrazines
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A facile route to aryl N-aminosulfonamides under mild conditions is provided. The reaction of aromatic amines (including heteroaromatic amines), sulfur dioxide, and hydrazines proceeds efficiently with good functional group tolerance. The in situ generated diazonium ion is involved in the aminosulfonylation process. This journal is the Partner Organisations 2014.
- Zheng, Danqing,Li, Ying,An, Yuanyuan,Wu, Jie
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supporting information
p. 8886 - 8888
(2014/08/05)
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- Metal-free aminosulfonylation of aryldiazonium tetrafluoroborates with DABCO×(SO2)2 and hydrazines
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The coupling of aryldiazonium tetrafluoroborates, DABCO×(SO 2)2, and hydrazines under metal-free conditions leads to the formation of aryl N-aminosulfonamides. The reaction proceeds smoothly at room temperature and shows broad functional-group tolerance. A radical process is proposed for this transformation. The coupling of aryldiazonium tetrafluoroborates, DABCO×(SO2)2, and hydrazines under metal-free conditions leads to the formation of aryl N-aminosulfonamides. The reaction proceeds under mild reaction conditions, is fast, has a broad substrate scope, and gives the products in high yiels (21 examples). A plausible mechanism that involves a radical process is also proposed. Copyright
- Zheng, Danqing,An, Yuanyuan,Li, Zhenhua,Wu, Jie
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supporting information
p. 2451 - 2454
(2014/03/21)
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- Palladium-catalyzed aminosulfonylation of aryl iodides by using Na 2SO3 as the SO2 source
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We realized an interesting palladium-catalyzed aminosulfonylation of aryl iodides by using Na2SO3 as a cheap SO2 source. In most cases, the yields were comparable to those reported by using the 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABCO·2SO 2, DABSO) as the SO2 source. Copyright
- Li, Wanfang,Li, Haoquan,Langer, Peter,Beller, Matthias,Wu, Xiao-Feng
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supporting information
p. 3101 - 3103
(2014/06/09)
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- One-pot three-component sulfone synthesis exploiting palladium-catalysed aryl halide aminosulfonylation
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A palladium-catalysed aminosulfonylation process is used as the key-step in a one-pot, three-component sulfone synthesis. The process combines aryl-, heteroaryl- and alkenyl iodides with a sulfonyl unit and an electrophilic coupling fragment. The sulfonyl unit is delivered in the form of an aminosulfonamide, which then serves as a masked sulfinate. The sulfinate is combined, in situ, with an electrophilic coupling partner, such as a benzylic, allylic or alkyl halide, an electron-poor arene, or a cyclic epoxide, to provide the corresponding sulfone products in good to excellent yields. The mild reaction conditions and use of commercially available reaction components allows the easy preparation of a broad range of sulfones featuring a variety of functional groups. The process obviates the need to employ thiol starting materials, and oxidative operations.
- Richards-Taylor, Charlotte S.,Blakemore, David C.,Willis, Michael C.
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p. 222 - 228
(2014/01/06)
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- A palladium-catalyzed three-component coupling of arylboronic acids, sulfur dioxide and hydrazines
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A novel and efficient route to aryl N-aminosulfonamides via a palladium-catalyzed three-component coupling of arylboronic acids, sulfur dioxide and hydrazines in the presence of a balloon of dioxygen is reported. The reaction proceeded smoothly under mild conditions and DABCO·(SO 2)2 was used as the source of sulfur dioxide.
- Ye, Shengqing,Wu, Jie
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supporting information; experimental part
p. 7753 - 7755
(2012/09/21)
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- Palladium-catalysed aminosulfonylation of aryl-, alkenyl- and heteroaryl halides: Scope of the three-component synthesis of N-aminosulfonamides
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By using DABCO·(SO2)2, DABSO, as a solid bench-stable SO2-equivalent, the palladium-catalysed aminosulfonylation of aryl-, alkenyl- and heteroaryl halides has been achieved. N,N-Dialkylhydrazines are employed as the N-nucleophiles and provide N-aminosulfonamides as the products in good to excellent yields. The reactions are operationally simple to perform, requiring only a slight excess of SO 2 (1.2-2.2 equiv.), and tolerate a variety of substituents on the halide coupling partner. Variation of the hydrazine component is also demonstrated. The use of N,N-dibenzylhydrazine as the N-nucleophile delivers N-aminosulfonamide products that can be converted into the corresponding primary sulfonamides using a high-yielding, telescoped, deprotection sequence. The ability to employ hydrazine·SO2 complexes as both the N-nucleophile and SO2 source is also illustrated.
- Emmett, Edward J.,Richards-Taylor, Charlotte S.,Nguyen, Bao,Garcia-Rubia, Alfonso,Hayter, Barry R.,Willis, Michael C.
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supporting information; experimental part
p. 4007 - 4014
(2012/06/04)
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- A palladium-catalyzed reaction of aryl halides, potassium metabisulfite, and hydrazines
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Aryl N-aminosulfonamides could be easily produced via a palladium-catalyzed coupling of aryl halides, potassium metabisulfite, and hydrazines. Potassium metabisulfite is an excellent equivalent of sulfur dioxide in the reaction of palladium-catalyzed aminosulfonylation. The Royal Society of Chemistry 2012.
- Ye, Shengqing,Wu, Jie
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supporting information
p. 10037 - 10039
(2012/11/06)
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- DABCO-bis (sulfur dioxide), DABSO, as a convenient source of sulfur dioxide for organic synthesis: Utility in sulfonamide and sulfamide preparation
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The charge-transfer complex generated from the combination of DABCO and sulfur dioxide, DABSO, is a bench-stable colorless solid suitable for use in organic synthesis as a replacement for gaseous sulfur dioxide. The complex can be combined with Grignard reagents to form sulfinates, which can then be converted in situ to a series of sulfonamides. Alternatively, reaction with anilines and iodine leads to the formation of a series of sulfamides. Cheletropic addition between DABSO and 2,3-dimethylbutadiene provides the corresponding sulfolene.
- Woolven, Holly,Gonzalez-Rodriguez, Carlos,Marco, Isabel,Thompson, Amber L.,Willis, Michael C.
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p. 4876 - 4878
(2011/12/05)
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- Palladium-catalyzed aminosulfonylation of aryl halides
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The palladium-catalyzed three-component coupling of aryl iodides, sulfur dioxide, and hydrazines to deliver aryl N-aminosulfonamides is described. The colorless crystalline solid DABCO· (SO2)2 was used as a convenient source of sulfur dioxide. The reaction tolerates significant variation of both the aryl iodide and hydrazine coupling partners.
- Nguyen, Bao,Emmett, Edward J.,Willis, Michael C.
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supporting information; experimental part
p. 16372 - 16373
(2011/02/22)
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- One-Pot synthesis of sulfonamides from primary and secondary amine derived sulfonate salts using cyanuric chloride
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A convenient, mild and efficient one-pot synthesis of new sulfonamides is described. The reaction of primary or secondary amine derived sulfonate salts in the presence of cyanuric chloride, triethylamine as base, and anhydrous acetonitrile as solvent at room temperature gives the corresponding sulfonamides in good to excellent yields. Georg Thieme Verlag Stuttgart.
- Rad, Mohammad Navid Soltani,Khalafi-Nezhad, Ali,Asrari, Zeinab,Behrouz, Somayeh,Amini, Zohreh,Behrouz, Marzieh
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experimental part
p. 3983 - 3988
(2010/03/26)
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