- Palladium-Catalyzed ortho-Benzoylation of Sulfonamides through C?H Activation: Expedient Synthesis of Cyclic N-Sulfonyl Ketimines
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The ortho-carbonylation of sulfonylarenes by non-hazardous aryl aldehydes as a carbonyl precursor was reported. In this method, the sulfonamide group serves as a directing group for C?H activation in the presence of a Pd catalyst under ligand-free conditions. The scope of this strategy has been extended to the one-pot two-step synthesis of cyclic N-sulfonyl ketimines under mild reaction conditions. Our approach could be considered as an alternative by circumventing the use of highly reactive organolithium or Grignard reagents to access a wide range of biologically potent cyclic N-sulfonyl ketimines. (Figure presented.).
- Ojha, Subhadra,Panda, Niranjan
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p. 561 - 571
(2019/12/24)
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- One-Pot Substitution of Aliphatic Alcohols Mediated by Sulfuryl Fluoride
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The Mitsunobu reaction is a powerful transformation for the one-pot activation and substitution of aliphatic alcohols. Significant efforts have focused on modifying the classic conditions to overcome problems associated with purification from phosphine-based byproducts. Herein, we report a phosphine free method for alcohol activation and substitution that is mediated by sulfuryl fluoride. This new method is effective for a wide range of primary alcohols using phthalimide, di-tert-butyl-iminodicarboxylate, and aromatic thiol nucleophiles in 74 % average yield. Activated carbon nucleophiles and a deactivated phenol were also effective for this reaction in good yields. Secondary alcohols were also successful substrates using aryl thiols, affording the corresponding sulfides in 56 % average yield with enantiomeric ratios up to 99:1. This new protocol has a distinct synthetic advantage over many existing phosphine-based methods as the byproducts are readily separable. This feature was exploited in several examples that did not require chromatography for purification. Furthermore, the mild reaction conditions enabled further in situ derivatization for the one-pot conversion of alcohols to amines or sulfones. This method also provides a boarder nucleophile scope compared to existing phosphine-free methods.
- Dubois, Rudy,Epifanov, Maxim,Hodgson, Jack W.,Mo, Jia Yi,Sammis, Glenn M.
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supporting information
p. 4958 - 4962
(2020/04/22)
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- Deoxyalkoxyamination of Alcohols for the Synthesis of N-Alkoxy-N-alkylbenzenesulfonamides
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A novel protocol for the deoxyalkoxyamination of alcohols has been developed, using N-alkoxybenzenesulfonimide (NOSI) as both a sulfonyl transfer reagent and an alkoxyamine source, accessing a diverse range of N-alkoxy-N-alkylbenzenesulfonamides with excellent isolated yields. This method is characterized by metal-free reaction, scalability, and waste-balance. Chiral substrates are converted with excellent levels of stereochemical inversion. NOSI could be generated in situ during the reaction as a stable reagent if a three-component one-pot reaction was designed. Exploiting this approach to run intramolecular reactions offered various N-protected isoxazolidines. In addition, valuable O-alkyl hydroxylamines (or isoxazolidines) were obtained through a neutral strategy of desulfonylation of the products.
- Sun, Qi-An,Lu, Ze-Hai,Pu, Xiao-Qiu,Hu, Hui-Lian,Zhang, Jia-heng,Yang, Xian-Jin
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supporting information
p. 3920 - 3927
(2018/07/31)
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- Benzenesulfonylation reagent as well as preparation method and application thereof
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The invention discloses a benzenesulfonylation reagent. The structure of the benzenesulfonylation reagent is shown as formula I in the specification, wherein R is a benzene ring connected with 0-5 substituents, and the substituents on the benzene ring are chlorine atoms, fluorine atoms, methyl groups or tert-butyl groups independently. The invention further discloses a preparation method and an application of the benzenesulfonylation reagent. The benzenesulfonylation reagent is prepared from methoxyamine hydrochloride and benzenesulfonyl chloride or a benzenesulfonyl chloride derivative through two steps of reactions, raw materials are cheap, a preparation process is simple, reaction conditions are mild, few side effects are produced, only extraction and simple column chromatographic purification are needed for aftertreatment, and the yield is high. The benzenesulfonylation reagent has higher benzenesulfonylation activity, benzenesulfonylation reaction conditions are mild, a reaction substrate range is wider, compounds such as alcohol, phenol, naphthol, thiophenol and the like can be subjected to a benzenesulfonylation reaction in presence of acetonitrile neutralized potassium carbonate, and -C1 does not exist on the benzenesulfonylation reagent, so that HCl gas with pungent odor cannot be emitted during application.
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Paragraph 0031; 0032; 0033; 0034; 0035
(2017/07/21)
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- N-Chloro-N-methoxybenzenesulfonamide: A Chlorinating Reagent
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A structurally simple and reactive chlorinating reagent, N-chloro-N-methoxybenzenesulfonamide, was conveniently and economically prepared in high yield. 1,3-Diketones, β-keto esters, benzoyl trifluoroacetones, phenols, anisoles, heteroarenes, and aromatic amines were successfully chlorinated, and the products were obtained in good to high yields.
- Pu, Xiaoqiu,Li, Qingwei,Lu, Zehai,Yang, Xianjin
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supporting information
p. 5937 - 5940
(2016/12/26)
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