Search results for "Tetrahydropyran"
showing 10 items of 15 documents
CCDC 941095: Experimental Crystal Structure Determination
2013
Related Article: Christoph Gütz, Rainer Hovorka, Caroline Stobe, Niklas Struch, Filip Topić, Gregor Schnakenburg, Kari Rissanen, Arne Lützen|2014|Eur.J.Org.Chem.|2014|206|doi:10.1002/ejoc.201301314
Diastereoselective synthesis of substituted 2-phenyltetrahydropyrans as useful precursors of aryl C-glycosides via selenoetherification
2004
The cyclization of several substituted 5-phenyl-pent-4-en-1-ols with selenium electrophiles along some mechanistic considerations is discussed. In particular, an efficient diastereoselective synthesis of a 2,3,5,6-tetrasubstitued tetrahydropyran is reported. These findings open an interesting approach: the use of chiral selenium electrophiles for cyclization of chiral substrates. The cyclized products are useful starting material for the synthesis of D- or L-aryl C-glycosides.
Stereoselective synthesis of substituted tetrahydropyran rings via 6-exo and 6-endo selenoetherification
2002
Eight unsaturated alcohols were cyclized by selenoetherification in 6-exo or 6-endo manner to give substituted tetrahydropyran rings. Yields, regio- and stereoselectivities were discussed in terms of steric and electroniceffects such as Se-O interaction. For the first time examples of the use of silica gel in selenoetherification and the effect of the X - counter ion of PhSe + on the reaction course are discussed. These effects are related to the occurrence of Se-O interaction.
Über die elementarprozesse bei der anionischen polymerisation des styrols in tetrahydropyran (THP)
1972
Kinetische und konduktometrische Messungen am System Polystyrl-Natrium in THP werden mit dem Ziel durchgefuhrt, alle in dem fruher vorgeschlagenen dreiteiligen Reaktionsschema vorkommenden thermodynamischen und kinetischen Parameter zu bestimmen und mit den in anderen Losungsmitteln gefundenen Werten zu vergleichen. Es zeigt sich, das die Geschwindigkeitskonstanten der Monomeraddition an das Kontaktionenpaar, das solvatgetrennte Ionenpaar und das freie Anion, die sich um Grosenordnungen unterscheiden, vom Losungsmittel nur geringfugig beeinflust werden. Der ungewohnlich grose Einflus der Losungsmittel auf die Polymerisationsgeschwindigkeit geschieht durch Verschiebung der Gleichgewichte zwi…
CCDC 229785: Experimental Crystal Structure Determination
2004
Related Article: B.Kranke, D.Hebrault, M.Schultz-Kukula, H.Kunz|2004|Synlett|2004|671|doi:10.1055/s-2004-817775
CCDC 945021: Experimental Crystal Structure Determination
2013
Related Article: Christoph Gütz, Rainer Hovorka, Caroline Stobe, Niklas Struch, Filip Topić, Gregor Schnakenburg, Kari Rissanen, Arne Lützen|2014|Eur.J.Org.Chem.|2014|206|doi:10.1002/ejoc.201301314
CCDC 1003004: Experimental Crystal Structure Determination
2014
Related Article: Christoph Gütz , Rainer Hovorka , Niklas Struch , Jens Bunzen , Georg Meyer-Eppler , Zheng-Wang Qu , Stefan Grimme , Filip Topić, Kari Rissanen, Mario Cetina, Marianne Engeser, Arne Lützen|2014|J.Am.Chem.Soc.|136|11830|doi:10.1021/ja506327c
Regioselective Epoxide Ring Opening. Steroselective Synthesis of a Tetrahydropyran Ring
1998
The stereoselective synthesis of a 2-substituted tetrahydropyran with adjacent alkoxy-bearing stereogenic centre is described. The key steps of this synthesis were the stereoselective epoxidation of an allylic alcohol and the regioselective epoxide ring opening by lithium aluminum hydride. The regio and stereoselective synthesis of a trihydroxyselenide and a trihydroxysulfide is also described. The latter compounds are not suitable for cyclization to tetrahydrofuran ring.
ChemInform Abstract: Stereoselective Synthesis of Substituted Tetrahydropyran Rings via 6-exo and 6-endo Selenoetherification.
2010
Eight unsaturated alcohols were cyclized by selenoetherification in 6-exo or 6-endo manner to give substituted tetrahydropyran rings. Yields, regio- and stereoselectivities were discussed in terms of steric and electroniceffects such as Se-O interaction. For the first time examples of the use of silica gel in selenoetherification and the effect of the X - counter ion of PhSe + on the reaction course are discussed. These effects are related to the occurrence of Se-O interaction.
1979
The kinetics of the anionic polymerization of styrene were investigated under pressure (1≤p/bar < 1800) with Na+ as counter ion in tetrahydropyran (THP) as solvent and with Cs+ as counter ion in 1,2-dimethoxyethane (DME) as solvent. The results yielded the activation volume of the contact ion pair ΔV and the sum (ΔV + ΔVcs) of the activation volume of the solvent separated ion pair ΔV and the volume change upon formation of solvent separated ion pairs from contact ion pairs ΔVcs. The numerical values are negative. The activation volume of the solvent separated ion pairs could be estimated.