The Experts below are selected from a list of 1851 Experts worldwide ranked by ideXlab platform
Fuqiang Jin - One of the best experts on this subject based on the ideXlab platform.
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Facile conversion of trifluoroacetyltriphenylsilane 2,4,6-triisepropylbenzenesulfonylhydrazone to 2,2,2-trifluorodiazoethane. An unusual example of the Bamford-Stevens Reaction
Tetrahedron Letters, 1992Co-Authors: Fuqiang JinAbstract:Abstract Trifluoroacetyltriphenylsilane 2,4,6-triisepropylbenzenesulfonylhydrazone( 1 ) reacted with dipolarophiles in the presence of Et 3 N to produce trifluorcmethylated pyrazoles or pyrazolines in good yields. The Reaction was found to proceed through the intermediacy of 2,2,2-trifluorodiazoethane, and this unusual co)nversion of 1 to 2,2,2-trifluorodiazoethane was studied from the mechanistic viewpoint.
Tim Bielfeldt - One of the best experts on this subject based on the ideXlab platform.
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Dirhodium(II) Tetraacetate Catalyzed (Chlorovinyl)cyclopropanation of Enol Ethers and Dienol Ethers - A Route to Donor-Substituted Vinylcyclopropanes, Ethynylcyclopropanes and Cycloheptadienes
Synthesis, 1991Co-Authors: Armin De Meijere, Thomas-jörn Schulz, R. R. Kostikov, Frank Graupner, Torsten Murr, Tim BielfeldtAbstract:2-chloro-(4-Cl), 3,3-dichloro- (4-Cl 2 ), and 2,3,3-trichlorodiazopropene (4-Cl 3 ) can easily be prepared in up to 70% yield by thermal fragmentation (Bamford-Stevens Reaction), at 60 o C in tetrahydrofuran, of the corresponding chloroacrolein tosylhydrazone sodium salts 3-Cl n . Tetrahydrofuran solutions of (chlorovinyl)diazomethanes 4-Cl n thus obtained are used for cyclopropanation Reactions of a large variety of alkenes
Javier De Vicente - One of the best experts on this subject based on the ideXlab platform.
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The Use of Tosylhydrazone Salts as a Safe Alternative for Handling Diazo Compounds and Their Applications in Organic Synthesis
European Journal of Organic Chemistry, 2005Co-Authors: J. Robin Fulton, Varinder K. Aggarwal, Javier De VicenteAbstract:Diazo compounds are useful synthetic intermediates in organic synthesis but, due to their toxicity and unpredictable explosive behaviour, their unique reactivity has not been fully exploited and their use on large scale has been avoided. We have developed a reliable method that generates diazo compounds in situ. Our approach is based on the Bamford-Stevens Reaction, which utilizes tosylhydrazone salts as diazo precursors. In the presence of phase-transfer-catalysts (PTC), we found that tosylhydrazone salts can be cleanly converted to diazo compounds under mild Reaction conditions and in a wide range of solvents. These diazo compounds can then be induced to react directly with alkenes or alkynes to synthesize pyrazoles or with aldehydes to generate ketones. Alternatively, diazo compounds can react with transition metals capable of carbene transfer Reactions. We have shown the usefulness of this chemistry in a number of different transformations, such as Wittig olefination Reactions and the sulfur ylide mediated epoxidation, as well as aziridination and cyclopropanation chemistry as applied toward the synthesis of more complicated molecules. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).
Armin De Meijere - One of the best experts on this subject based on the ideXlab platform.
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Dirhodium(II) Tetraacetate Catalyzed (Chlorovinyl)cyclopropanation of Enol Ethers and Dienol Ethers - A Route to Donor-Substituted Vinylcyclopropanes, Ethynylcyclopropanes and Cycloheptadienes
Synthesis, 1991Co-Authors: Armin De Meijere, Thomas-jörn Schulz, R. R. Kostikov, Frank Graupner, Torsten Murr, Tim BielfeldtAbstract:2-chloro-(4-Cl), 3,3-dichloro- (4-Cl 2 ), and 2,3,3-trichlorodiazopropene (4-Cl 3 ) can easily be prepared in up to 70% yield by thermal fragmentation (Bamford-Stevens Reaction), at 60 o C in tetrahydrofuran, of the corresponding chloroacrolein tosylhydrazone sodium salts 3-Cl n . Tetrahydrofuran solutions of (chlorovinyl)diazomethanes 4-Cl n thus obtained are used for cyclopropanation Reactions of a large variety of alkenes
Volker Schlicht - One of the best experts on this subject based on the ideXlab platform.
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Structure–odour correlation, part XXV. Synthesis of dehydro‐ and dihydrosesquicineole
Flavour and Fragrance Journal, 1998Co-Authors: Peter Weyerstahl, Volker SchlichtAbstract:Dehydrosesquicineole (1), a sesquiterpene ether recently isolated from Artemisia sieberi, was synthesized starting from the bicyclic ketone 2a by a Bamford-Stevens Reaction via the hydrazone 2b. Catalytic hydrogenation of 1 gave selectively either sesquicineole (3,7-epoxybisabol-10-ene, 3) or dihydrosesquicineole (4). The odour strength decreases from 1 to 3 to 4; the odour quality with fruity and floral tonalities is similar
