- Direct Conversion of N-Alkylamines to N-Propargylamines through C-H Activation Promoted by Lewis Acid/Organocopper Catalysis: Application to Late-Stage Functionalization of Bioactive Molecules
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An efficient catalytic method to convert an α-C-H bond of N-alkylamines into an α-C-alkynyl bond was developed. In the past, such transformations were carried out under oxidative conditions, and the enantioselective variants were confined to tetrahydroisoquinoline derivatives. Here, we disclose a method for the union of N-alkylamines and trimethylsilyl alkynes, without the presence of an external oxidant and promoted through cooperative actions of two Lewis acids, B(C6F5)3 and a Cu-based complex. A variety of propargylamines can be synthesized in high diastereo-and enantioselectivity. The utility of the approach is demonstrated by the late-stage site-selective modification of bioactive amines. Kinetic investigations that shed light on various mechanistic nuances of the catalytic process are presented.
- Chan, Jessica Z.,Yesilcimen, Ahmet,Cao, Min,Zhang, Yuyang,Zhang, Bochao,Wasa, Masayuki
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supporting information
p. 16493 - 16505
(2020/10/26)
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- A silicon saisai fungus amine synthesis method
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The invention provides a synthetic method for silthiopham, which belongs to the technical field of organic synthesis. The objective of the invention is to overcome the problems of complicated synthesis process, a great number of byproducts and severe environmental pollution of conventional synthetic methods for silthiopham. The synthetic method provided by the invention comprises the following steps: (1) with trimethylsilylacetylene as a raw material, under the protection of inert gas, reacting trimethylsilylacetylene with methyl chloroformate under the action of organic base so as to obtain methyl (trimethylsilyl)propiolate; (2) reacting methyl (trimethylsilyl)propiolate with allyl amine in a solvent under the action of a catalyst so as to obtain N-allyl-3-(trimethylsilyl)propiolamide; and (3) subjecting N-allyl-3-(trimethylsilyl)propiolamide with 3-mercapto-2-butanone to a heating reflux reaction under the action of an alkali catalyst and carrying out dehydration so as to obtain the final product silthiopham. The method has the advantages of usage of cheap and easily available raw materials, simple route, high yield and no usage of reagents severely polluting the environment, e.g., t-butyl nitrous acid and thionyl chloride.
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Paragraph 0035-0037
(2019/04/02)
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- NHC catalysed trimethylsilylation of terminal alkynes and indoles with Ruppert's reagent under solvent free conditions
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An organo-catalytic protocol for the trimethylsilylation of terminal alkynes employing Ruppert's reagent (CF3SiMe3) as a trimethylsilyl source has been developed under solvent and fluoride free conditions. This method was found to be very effective as a variety of terminal alkynes bearing aliphatic or aromatic substituents underwent smooth transformation to their corresponding silylated products in excellent yields within a few minutes using N-heterocyclic carbene as an organo-catalyst. This methodology was also applied to the chemospecific N-silylation of indoles. This journal is
- Arde, Panjab,Reddy, Virsinha,Anand, Ramasamy Vijaya
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p. 49775 - 49779
(2014/12/11)
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- A convergent approach to (-)-callystatin a based on local symmetry
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The key is symmetry! A convergent synthetic approach of the highly cytotoxic natural product (-)-callystatin A was developed assembling three fragments through Julia-Kocienski olefination and Stille cross-coupling. The new strategy relies on a pivotal local symmetry of the target molecule. In this preliminary study, particular attention was devoted to facilitate the catalytic enantiocontrol of strategic stereogenic centers present in each of the fragments (see scheme). Copyright
- Candy, Mathieu,Tomas, Lo?c,Parat, Sabrina,Heran, Virginie,Bienaymé, Hugues,Pons, Jean-Marc,Bressy, Cyril
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supporting information
p. 14267 - 14271
(2013/01/15)
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- Metal-free 1,5-regioselective azide-alkyne [3+2]-cycloaddition
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[3+2]-cycloaddition reactions of aromatic azides and silylated alkynes in aqueous media yield 1,5-disubstituted-4-(trimethyl-silyl)-1H-1,2,3-triazoles. The formation of the 1,5-isomer is highly favored in this metal-free cycloaddition, which could be proven by 1D selective NOESY and X-ray investigations. Additionally, DFT calculations corroborate the outstanding favoritism regarding the 1,5-isomer. The described method provides a simple alternative protocol to metal-catalyzed "click chemistry" procedures, widening the scope for regioselective heavy-metal-free synthetic applications.
- Kloss, Florian,Koehn, Uwe,Jahn, Burkhard O.,Hager, Martin D.,Goerls, Helmar,Schubert, Ulrich S.
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supporting information; experimental part
p. 2816 - 2824
(2012/06/01)
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- Cesium Salt-Catalyzed Addition of Diphenyl Dichalcogenides to Alkynes: Selective Synthesis of Bis- and Mono(phenylchalcogeno)alkenes
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A cesium salt has a unique catalytic ability for the reaction of alkynes with diphenyl dichalcogenides. When the diphenyl dichalcogenides, such as the disulfide, diselenide, or ditelluride, were allowed to react with alkynes in the presence of a catalytic
- Nishiyama, Yutaka,Ohnishi, Haruko,Koguma, Yuya
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experimental part
p. 1170 - 1174
(2009/12/25)
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- A very short, efficient and inexpensive synthesis of the prodrug form of SC-54701A. A platelet aggregation inhibitor
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A short and efficient synthesis of the prodrug form of SC-54701A has been achieved from (trimethylsilyl)acetylene in 6 steps with an overall yield of 19%.
- Cossy,Schmitt,Cinquin,Buisson,Belotti
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p. 1699 - 1700
(2007/10/03)
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- Organic Heterocyclothiazenes. Part 6. Improved Synthesis of Trithiadiazepines from Tetrasulphur Tetranitride and Alkynes
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In the reaction of tetrasulphur tetranitride, S4N4, with alkynes to give 1,3,5,2,4-trithiadiazepines, 1,3,5,2,4,6-trithiatriazepines, and 1,2,4- and 1,2,5-thiadiazoles, the yields of trithiadiazepines are often greatly improved (up to 8-fold) by the presence of Lewis acids, particularly titanium(IV) chloride.Thus the yield of dimethyl 1,3,5,2,4-trithiadiazepine-6,7-dicarboxylate (1) from dimethyl acetylenedicarboxylate (DMAD) is increased from 5 to 40 percent, formation of the trithiatriazepine (2) being totally suppressed.Trithiadiazepine formation is also much enhanced (up to 5-fold) at higher reaction temperatures (150-160 deg C) than previously used (80-110 deg C), though it varies very little with solvent polarity.
- Dunn, Peter J.,Rees, Charles W.
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p. 1585 - 1592
(2007/10/02)
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- Silylated Biphenyl Derivatives, Ethyl Benzoates, and Benzophenones by Regioselective -Cycloadditions
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The cycloaddition of the N-methyl-2-pyridones 1a-d with phenyl(trimethylsilyl)ethyne (2) proceeds regioselectively to give silylated biphenyl derivatives 5a, 6b, 5c,d.Similarly the reactions of ethyl (trimethylsilyl)propiolate (3) and of benzoyl(trimethylsilyl)ethyne (4) with 1a-c afford the silylated ethyl benzoates 5e, 6f, 5g and the benzophenones 5h, 6i, 5j, respectively.
- Birkofer, Leonhard,Wahle, Bernd
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p. 3309 - 3315
(2007/10/02)
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