1076-13-7Relevant articles and documents
Tetraols as templates for the synthesis of large endo-functionalized macrocycles
Stoltenberg, Dennis,Luethje, Sonja,Winkelmann, Ole,Naether, Christian,Luening, Ulrich
experimental part, p. 5845 - 5859 (2011/12/05)
Forty-six- and fifty-membered endo-functionalized macrocycles were obtained by template syntheses with new stiff tetracyclic tetraols 10 and 11. Reaction of dialkenylatedboronic acids 1 with template molecules 10 and 11 generated preorganized bisboronic esters 18 and 19, which were cyclized by ring-closing olefin metathesis. Resulting bimacrocycles 20 and 21 were obtained in ca. 60% yield when alkenyl chains of sufficient lengths were used. The E/E, E/Z, and Z/Z mixtures were hydrogenated to give saturated bimacrocycles 24 and 25 in excellent yields. The removal of the tetraol templates was possible by hydrolysis in the presence of dimethyl sulfate, which was needed to trap the liberated template. Thus, bis-endo-boronic acids 27e and 27f were obtained. The relative stereochemistry of the diastereoisomeric templates and the bimacrocyclic nature of the cyclization products were proven by X-ray structure analyses (for 12 and 26d).
Preparation and functionalisation of emulsion-derived microcellular polymeric foams (polyHIPEs) by ring-opening metathesis polymerisation (ROMP)
Deleuze, Herve,Faivre, Romain,Herroguez, Valerie
, p. 2822 - 2823 (2007/10/03)
Emulsion-derived microcellular polymeric foams (poly-HIPEs) have been prepared by ring opening metathesis polymerisation of a norbornene derivative using a Grubb's catalyst. The resulting material has been further function-alised using the active catalytic sites remaining on its structure.
Rearrangement and Cycloreversion of Diels-Alder Adducts of Cyclic 1,3-Dienes to Norbornadienes. A Novel homo-Cope Rearrangement. Evidence for Competitive Pericyclic and Diradical Processes
Hochstrate, Dirk,Klaerner, Frank-Gerrit
, p. 745 - 754 (2007/10/02)
On thermolysis of endo,endo-5, endo,endo-17, and endo,exo-17 ( the endo,endo and endo,exo Diels-Alder adducts of cyclopentadiene 7 or dimethylfulvene 15 to norbornadiene 8 or 7-isopropylidenenorbornadiene 20), a novel type of homo-Cope rearrangement leading to 6, 21, and 23a, respectively, competes with the retro-Diels-Alder reactions.According to a force-field analysis of the kinetic parameters, the competitive reactions (rearrangement and retro-Diels-Alder reaction) of endo,endo-5 occur in a pericyclic fashion whereas in the isopropylidene-substituted systems stepwise processes compete with the corresponding pericyclic reactions.Indirect experimental evidence for this assumption comes from a stereochemical analysis of the retro-Diels-Alder reaction in the cis-5,6-dideuterionorbornene derivatives exo-36-d2, endo-36-d2 and exo-39-d2, endo-39-d2 occuring stereospecifically in the case of exo-36-d2, endo-36-d2 and non-stereospecifically in the case of exo-39-d2, endo-39-d2.The change in mechanism rationalized by a different (allyl vs. pentadienyl) stabilization of the potential diradical intermediates in the stepwise reactions. - Key Words: Kinetic parameters / Stepwise and pericyclic reactions / Calculations, force field / Calculations of transition-state resonance energy (energy of concert)
Dechlorination reactions of hexachlorinated polycyclic compounds using ultra-sound radiation
Uberti Costa,Mollmann,Belli Riatto
, p. 2091 - 2097 (2007/10/02)
Dechlorination reactions of exo-endo and endo-endo perhalogenated tetracyclic compounds with Li/t-BuOH/THF system, when subjected to simultaneous ultra-sound irradiation, led to exceptionally high yields (77-95%) of the corresponding hydrocarbons.
