- Photochemical Approach to the Cyclohepta[b]indole Scaffold by Annulative Two-Carbon Ring-Expansion
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We report on the implementation of the concept of a photochemically elicited two-carbon homologation of a π-donor–π-acceptor substituted chromophore by triple-bond insertion. Implementing a phenyl connector between the slide-in module and the chromophore enabled the synthesis of cylohepta[b]indole-type building blocks by a metal-free annulative one-pot two-carbon ring expansion of the five-membered chromophore. Post-irradiative structural elaboration provided founding members of the indolo[2,3-d]tropone family of compounds. Control experiments in combination with computational chemistry on this multibond reorganization process founded the basis for a mechanistic hypothesis.
- Tymann, Dina Christina,Benedix, Lars,Iovkova, Lyuba,Pallach, Roman,Henke, Sebastian,Tymann, David,Hiersemann, Martin
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supporting information
p. 11974 - 11978
(2020/08/21)
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- Comparison of conventional and microwave-assisted synthesis of some new sulfenamides under free catalyst and ligand
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Abstract: Sulfenamide and its derivatives (S–N bond) have been synthesized with classical method in the literature. However, microwave-assisted synthesis of a series of N-(substituted phenylthio), N-(benzylthio), N-(cyclothio), and N-(2-mercaptobenzimidazolyl)amines has been not in the literature yet. They have been obtained from treating some amines (4?mmol) with thiophthalimides (PhthSR, 1?mmol) using sulfur transfer reagent in the presence of 2-ethoxyethanol (β-ee, neat) under microwave irradiation at 50?°C. The scope of this reaction was shown by the efficient synthesis of sulfenamides in good to excellent yields of 70–98% under free catalyst and ligand. Nine of the synthesized sulfenamide derivatives are novel. All of the thiols react with morpholine to give corresponding sulfenamides in excellent yields of 78–98%. Thiophenol, 4-methylthiophenol, 4-chlorothiophenol, and 4-fluorothiophenol react with cyclohexylamine to give corresponding sulfenamides in high yields 81–92%. Thiophenol, 4-methylthiophenol, 4-chlorothiophenol react with pyrrolidine to give corresponding sulfenamides in good yields of 70–76%. We observed that the reaction of t-butylamine with N-(phenylthio)phthalimide gave desired sulfenamide under microwave irradiation in the presence of DPPH as radical scavenger reagent in high yield of 93%. Aniline, benzylamine, 1-hexylamine, ethanolamine, diethylamine, N-ethyl-n-butylamine, N-ethylaniline, N-benzylmethylamine, t-butylamine react with thiols to give symmetrical disulfides instead of desired products under microwave irradiation, 2-ethoxyethanol as a solvent (neat), and at 50?°C. In this study, microwave-assisted synthesis method was compared with the classical method. All the products obtained were purified with chromatographic method and the analysis of these products was confirmed with IR, 1H NMR, 13C NMR spectroscopy, MS spectrometry, and elemental methods. Graphical abstract: [Figure not available: see fulltext.].
- Yakan, Hasan,Kütük, Halil
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p. 2047 - 2057
(2018/09/25)
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- Copper-catalyzed formation of sulfur-nitrogen bonds by dehydrocoupling of thiols with amines
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Copper-catalyzed formation of sulfur-nitrogen bonds can be performed by a dehydrocoupling of aryl thiols with amines. Sulfenamides or sulfonamides can be produced by the use of a copper catalyst in air or under oxygen atmosphere. Furthermore, a reaction involving the combination of a palladium catalyst and a copper catalyst selectively afforded sulfinamides.
- Taniguchi, Nobukazu
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scheme or table
p. 2670 - 2673
(2010/07/18)
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- Copper-catalyzed synthesis of sulfenamides utilizing diaryl disulfides with alkyl amines
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The copper-catalyzed coupling of diaryl disulfides with alkyl amines can afford various sulfenamides in good yields. Furthermore, the present reaction is efficient and can be used for both of the aryl sulfide groups on disulfide. Georg Thieme Verlag Stutt
- Taniguchi, Nobukazu
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p. 1917 - 1920
(2008/03/13)
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- N-tert-Butylbenzenesulfenamide-catalyzed oxidation of alcohols to the corresponding carbonyl compounds with N-chlorosuccinimide
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N-tert-Butylbenzenesulfenamide (1)-catalyzed oxidation of various primary and secondary alcohols to the corresponding aldehydes and ketones was efficiently carried out by using N-chlorosuccinimide (NCS) in the coexistence of potassium carbonate and molecular sieves 4? at easy-to-control temperatures ranging from 0°C to room temperature. The present catalytic oxidation was performed without giving any damage to the functional groups in alcohols, and was particularly effective in the oxidation of alcohols that formed labile aldehydes because of its mild reaction conditions. Further, selective oxidation of primary hydroxy groups took place in 1-catalyzed oxidation of several diols. Mechanistic investigation suggested that the chlorination of the sulfenamide 1 by NCS led to the formation of a key species, N-tert-butylbenzenesulfinimidoyl chloride (2), which in turn oxidized alcohols in the presence of potassium carbonate to afford carbonyl products by accompanying regeneration of the catalyst 1.
- Matsuo, Jun-Ichi,Iida, Daisuke,Yamanaka, Hiroyuki,Mukaiyama, Teruaki
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p. 6739 - 6750
(2007/10/03)
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- A new method for oxidation of various alcohols to the corresponding carbonyl compounds by using n-t-butylbenzenesulfinimidoyl chloride
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Various primary and secondary alcohols were smoothly oxidized to the corresponding aldehydes and ketones by using a new oxidizing agent, N-t-butylbenzenesulfinimidoyl chloride (4a), in the coexistence of DBU or zinc oxide. The present oxidation proceeded under mild conditions via five-membered intramolecular proton-transfer of an alkyl arenesulfinimidate intermediate.
- Matsuo, Jun-Ichi,Iida, Daisuke,Tatani, Kazuya,Mukaiyama, Teruaki
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p. 223 - 234
(2007/10/03)
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- Sulfenamide catalyzed oxidation of alcohols to the corresponding carbonyl compounds with anhydrous chloramine-T.
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N-tert-Butylbenzenesulfenamide (1) catalyzed oxidation of various alcohols with stoichiometric amount of anhydrous chloramines-T (2) proceeded smoothly at room temperature to afford the corresponding carbonyl compounds in good yields.
- Kitagawa, Hideo,Mukaiyama, Teruaki
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p. 1276 - 1279
(2007/10/03)
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- A new sulfenylation reagent, 3-phenylsulfenyl-2-(N- cyanoimino)thiazolidine, and its optically active version
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We have developed a new sulfenylation reagent, 3-phenylsulfenyl-2-(N- cyanoimino)thiazolidine 3, that is readily available and stable upon storage. Compound 3 easily reacts with amines or thiols to give the corresponding sulfenamides or asymmetrical disulfides in excellent yields. It was also found that the α-sulfenylation reaction of carbonyl compounds with 3 proceeds smoothly. Furthermore, optically active 4-diphenylmethyl derivative 4 was synthesized as an asymmetric sulfenylation reagent, which realized 96% e.e. upon α-sulfenylation of a cyclic β-keto ester.
- Tanaka,Azuma,Fang,Uchida,Iwata,Ishida,In,Maezaki
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