The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Raquel G. Jacob - One of the best experts on this subject based on the ideXlab platform.
-
Selenonium ionic liquid as efficient catalyst for the Baylis-Hillman reaction
Tetrahedron Letters, 2009Co-Authors: Eder J. Lenardão, Gelson Perin, Raquel G. Jacob, Josiane De Oliveira Feijó, Samuel Thurow, Claudio C. SilveiraAbstract:Abstract The new acidic ionic liquid phenyl butyl ethyl Selenonium tetrafluoroborate, [pbeSe]BF 4 , was successful used as a co-catalyst in the Baylis–Hillman reaction of aldehydes and electron-deficient alkenes. The Baylis–Hillman adducts were obtained in moderated to good yields and in relatively short reaction times under mild conditions.
-
Selenonium ionic liquid as an efficient catalyst for the synthesis of thioacetals under solvent-free conditions
Tetrahedron Letters, 2008Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Gelson Perin, Elton L. Borges, Raquel G. JacobAbstract:Abstract Acidic ionic liquid butyl ethyl phenyl Selenonium tetrafluoroborate, [BEPSe]BF4, was successfully employed as a catalyst for the synthesis of several dithioacetals in the absence of a solvent. The method is general and selectively afforded thioacetals derived from aldehydes and ketones in good yields.
-
Selenium- and tellurium-based ionic liquids and their use in the synthesis of octahydroacridines
Tetrahedron Letters, 2006Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Patricia C. Ferreira, Gelson Perin, Claudio C. Silveira, Raquel G. JacobAbstract:Abstract A general and easy method for the synthesis of several Selenonium and telluronium salts is described. These compounds are acidic liquids at room temperature and were obtained in excellent yields. Phenyl butyl ethyl Selenonium tetrafluoroborate was employed in the hetero-Diels–Alder cyclization of aryl imines derived from citronellal, affording octahydroacridines in good yields.
Eder J. Lenardão - One of the best experts on this subject based on the ideXlab platform.
-
Sweet Selenium: Synthesis and Properties of Selenium-Containing Sugars and Derivatives
Pharmaceuticals (Basel Switzerland), 2020Co-Authors: Francesca Mangiavacchi, Ítalo F. C. Dias, Irene Di Lorenzo, Pawel Adam Grzes, Martina Palomba, Ornelio Rosati, Luana Bagnoli, Francesca Marini, Claudio Santi, Eder J. LenardãoAbstract:In the last decades, organoselenium compounds gained interest due to their important biological features. However, the lack of solubility, which characterizes most of them, makes their actual clinical exploitability a hard to reach goal. Selenosugars, with their intrinsic polarity, do not suffer from this issue and as a result, they can be conceived as a useful alternative. The aim of this review is to provide basic knowledge of the synthetic aspects of selenosugars, Selenonium salts, selenoglycosides, and selenonucleotides. Their biological properties will be briefly detailed. Of course, it will not be a comprehensive dissertation but an analysis of what the authors think is the cream of the crop of this interesting research topic.
-
Selenonium ionic liquid as efficient catalyst for the Baylis-Hillman reaction
Tetrahedron Letters, 2009Co-Authors: Eder J. Lenardão, Gelson Perin, Raquel G. Jacob, Josiane De Oliveira Feijó, Samuel Thurow, Claudio C. SilveiraAbstract:Abstract The new acidic ionic liquid phenyl butyl ethyl Selenonium tetrafluoroborate, [pbeSe]BF 4 , was successful used as a co-catalyst in the Baylis–Hillman reaction of aldehydes and electron-deficient alkenes. The Baylis–Hillman adducts were obtained in moderated to good yields and in relatively short reaction times under mild conditions.
-
Selenonium ionic liquid as an efficient catalyst for the synthesis of thioacetals under solvent-free conditions
Tetrahedron Letters, 2008Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Gelson Perin, Elton L. Borges, Raquel G. JacobAbstract:Abstract Acidic ionic liquid butyl ethyl phenyl Selenonium tetrafluoroborate, [BEPSe]BF4, was successfully employed as a catalyst for the synthesis of several dithioacetals in the absence of a solvent. The method is general and selectively afforded thioacetals derived from aldehydes and ketones in good yields.
-
Selenium- and tellurium-based ionic liquids and their use in the synthesis of octahydroacridines
Tetrahedron Letters, 2006Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Patricia C. Ferreira, Gelson Perin, Claudio C. Silveira, Raquel G. JacobAbstract:Abstract A general and easy method for the synthesis of several Selenonium and telluronium salts is described. These compounds are acidic liquids at room temperature and were obtained in excellent yields. Phenyl butyl ethyl Selenonium tetrafluoroborate was employed in the hetero-Diels–Alder cyclization of aryl imines derived from citronellal, affording octahydroacridines in good yields.
Gelson Perin - One of the best experts on this subject based on the ideXlab platform.
-
Selenonium ionic liquid as efficient catalyst for the Baylis-Hillman reaction
Tetrahedron Letters, 2009Co-Authors: Eder J. Lenardão, Gelson Perin, Raquel G. Jacob, Josiane De Oliveira Feijó, Samuel Thurow, Claudio C. SilveiraAbstract:Abstract The new acidic ionic liquid phenyl butyl ethyl Selenonium tetrafluoroborate, [pbeSe]BF 4 , was successful used as a co-catalyst in the Baylis–Hillman reaction of aldehydes and electron-deficient alkenes. The Baylis–Hillman adducts were obtained in moderated to good yields and in relatively short reaction times under mild conditions.
-
Selenonium ionic liquid as an efficient catalyst for the synthesis of thioacetals under solvent-free conditions
Tetrahedron Letters, 2008Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Gelson Perin, Elton L. Borges, Raquel G. JacobAbstract:Abstract Acidic ionic liquid butyl ethyl phenyl Selenonium tetrafluoroborate, [BEPSe]BF4, was successfully employed as a catalyst for the synthesis of several dithioacetals in the absence of a solvent. The method is general and selectively afforded thioacetals derived from aldehydes and ketones in good yields.
-
Selenium- and tellurium-based ionic liquids and their use in the synthesis of octahydroacridines
Tetrahedron Letters, 2006Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Patricia C. Ferreira, Gelson Perin, Claudio C. Silveira, Raquel G. JacobAbstract:Abstract A general and easy method for the synthesis of several Selenonium and telluronium salts is described. These compounds are acidic liquids at room temperature and were obtained in excellent yields. Phenyl butyl ethyl Selenonium tetrafluoroborate was employed in the hetero-Diels–Alder cyclization of aryl imines derived from citronellal, affording octahydroacridines in good yields.
Claudio C. Silveira - One of the best experts on this subject based on the ideXlab platform.
-
Selenonium ionic liquid as efficient catalyst for the Baylis-Hillman reaction
Tetrahedron Letters, 2009Co-Authors: Eder J. Lenardão, Gelson Perin, Raquel G. Jacob, Josiane De Oliveira Feijó, Samuel Thurow, Claudio C. SilveiraAbstract:Abstract The new acidic ionic liquid phenyl butyl ethyl Selenonium tetrafluoroborate, [pbeSe]BF 4 , was successful used as a co-catalyst in the Baylis–Hillman reaction of aldehydes and electron-deficient alkenes. The Baylis–Hillman adducts were obtained in moderated to good yields and in relatively short reaction times under mild conditions.
-
Selenium- and tellurium-based ionic liquids and their use in the synthesis of octahydroacridines
Tetrahedron Letters, 2006Co-Authors: Eder J. Lenardão, Samuel R. Mendes, Patricia C. Ferreira, Gelson Perin, Claudio C. Silveira, Raquel G. JacobAbstract:Abstract A general and easy method for the synthesis of several Selenonium and telluronium salts is described. These compounds are acidic liquids at room temperature and were obtained in excellent yields. Phenyl butyl ethyl Selenonium tetrafluoroborate was employed in the hetero-Diels–Alder cyclization of aryl imines derived from citronellal, affording octahydroacridines in good yields.
Tadashi Kataoka - One of the best experts on this subject based on the ideXlab platform.
-
The first isolation of allenylSelenonium salts: their synthesis and properties as electrophiles
Tetrahedron Letters, 2007Co-Authors: Shinichi Watanabe, Tatsunori Iwamura, Yukio Miura, Hideko Nagasawa, Tadashi KataokaAbstract:The first synthesis of allenylSelenonium salts and their reactivities are described. The corresponding allenyl methyl selenides were alkylated with methyl trifluoromethanesulfonate to afford the desired compounds. Their reactions with active methylene carbanions produced furan, dihydrofuran or methylene cyclopropane derivatives via the Michael addition of nucleophiles to the Selenonium salts.
-
The Formation of Cyclopropane Derivatives Bearing 1,2-Dicarbonyl Groups through Tandem Michael–Favorskii-Type Reactions with(E)-β-StyrylSelenonium Triflate
European Journal of Organic Chemistry, 2005Co-Authors: Shinichi Watanabe, Ippei Nakayama, Tadashi KataokaAbstract:A novel tandem Michael–Favorskii-type reaction is described. Treatment of active methylene carbanions, prepared by the reaction of NaH and active methylene compounds, with (E)-β-styrylSelenonium triflate in DMF at 70 °C for 3 h gave cyclopropane derivatives bearing 1,2-dicarbonyl groups in moderate to good yields. On the other hand, the carbanions derived from malonates reacted with the Selenonium salt to afford 1,1-dicarbonylcyclopropane compounds in good yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
-
Syntheses and reactions of cyclic se‐alkoxy‐se‐chloroselenuranes and alkoxySelenonium salts
Heteroatom Chemistry, 2001Co-Authors: Tadashi Kataoka, Tatsunori Iwamura, Hisayoshi Tsutsui, Yasuharu Kato, Yoshihiro Banno, Yasuko Aoyama, Hiroshi ShimizuAbstract:Several 1-chloro-2,1-oxaselenole selenuranes 3a–e and Selenonium salts 4a–c and 5-chloro-5,11-epoxy-6,11-dihydrodibenzo[b,e]selenepines 12a and 12b and Selenonium salts 13a–c were synthesized, and their reactions with organometallic reagents were studied. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:317–326, 2001
-
the first example of formation of the benzyne intermediate from the reactions of Selenonium salts with phenyllithium
Tetrahedron Letters, 1999Co-Authors: Tadashi Kataoka, Shinichi Watanabe, Keiichirou YamamotoAbstract:Abstract The reaction of diphenyl(phenylethynyl)Selenonium salt 1a with 1.0 equiv. of phenyllithium afforded 1,4-diphenylbutadiyne 5 and 1-(o-biphenylyl)-2-phenylethyne 7 in 25% and 15% yields, respectively. The latter product 7 was formed via the benzyne intermediate.
-
Reactions of Diphenyl(phenylethynyl)Selenonium Salts with Active Methylene Compounds and Amides : First Isolation of Oxyselenuranes[10-Se-4(C30)]as a Reaction Intermediate
The Journal of organic chemistry, 1998Co-Authors: Tadashi Kataoka, Shinichi Watanabe, Keiichirou Yamamoto, Mitsuhiro Yoshimatsu, Genzoh Tanabe, Osamu MuraokaAbstract:The reaction of the diphenyl(phenylethynyl)Selenonium triflate 1a with active methylene compounds 5 and t-BuOK in THF gave furan derivatives 6. The [10-Se-4(C3O)] selenuranes 8a and 8b could be isolated from the reactions with benzoylacetonitrile 5f and with 1,3-indandione 5g, respectively, as reaction intermediates. The structures of the selenuranes 8 were elucidated by X-ray crystallography and (77)Se high-resolution solid-state NMR spectroscopy. The selenuranes 8 underwent ligand coupling on standing at room temperature or refluxing in chloroform and gave the furan derivatives 6 and the ring-opened product 9. Similarly, the reaction of 1a with benzamide 13a and pivalamide 13d in the presence of NaH in THF afforded oxazole derivatives 14.