Norbornene

About: Norbornene is a research topic. Over the lifetime, 5628 publications have been published within this topic receiving 104495 citations. The topic is also known as: norbornylene & norcamphene.

Some Chlorine Derivatives of Norbornane (Bicyclo[2.2.1]heptane)

Abstract: The endo-cis and trans-5,6-dichloronorbornenes were prepared by the respective additions of cis- and trans-dichlorocthylene to cyclopentadiene. The sterochemical assigments were confirmed by dipole moment studies. The cis-dichloride was inert to hydrolysis while the trans isomer was hydrolyzed to 3,5-dihydroxynortricyclene. Hydrogenation of the dichloride isomers gave the endo-cis- and trans-2,3-dichloronorbornanes. Contrary to expectations based on preferential trans-elimination of hydrogen halide, the saturated cis-dichloride appeared to dehydrohalogenate somewhat less readily than the trans isomer, although the reaction was slow in both cases. Both isomers gave the same dehydrohalogenation product, 2-chloronorbornene, the structure of which was confirmed by oxidation to cis-cyclopentane-1,3-dicarboxylica cid and hydrolysis to norcamphor. Chlorination of norbornene at - 75o gave nortricyclyl chloride and syn-7-exo-2-dichloronorbornane. The structure of the latter was assigned (in preference to exo-cis-2,3-dichloronorbornane)because of the compound's relative inertness to dehydrohalogenating reagents. endo-cis-2,3-Dichloronorbornane was not readily hydrolyzed, but trans-2,3-dichloronorbornane and syn-7-exo-2-dichloronorbornane hydrolyzed to anti- and syn-7-exo-Z-norborneol, respectively. The syn-isomer also was obtained by addition of hypochlorous acid to norbornene. The structures of the chloro alcohols were inferred from their modes of formation and oxidation to chlorine-containing dicarboxylic acids which were presumed to be, respectively, trans- and cis-2-chloro-cis-cyclopentane-1,3-dicarboxylic acids. These acids were different from trans-and cis-4-chloro-cis-cyclopentane-1,3-dicarboxylic acids obtained by oxidation of exo- and endo-dehydronorbornyl chlorides, respectively. The assignments of the syn and anti configurations to the ketones were confirmed by dipole moment measurements. The syn and anti-chlorohydrins were converted by pyrolysis of their carboxylic acid esters in low yield to syn- and anti-7-chlorotiorbornenes. Each of the latter substances on hydrogenation gave the same compound, 7-chloronorbornane.

Induction of Smectic Layering in Nematic Liquid Crystals Using Immiscible Components. 5. Laterally Attached Side-Chain Liquid Crystalline Poly(norbornene)s and Their Low Molar Mass Model Compounds with Short Fluorocarbon Segments

Abstract: 5-[[[2‘,5‘-Bis[(4‘ ‘-n-((perfluoroalkyl)alkoxy)benzoyl)oxy]benzyl]oxy]carbonyl]bicyclo[2.2.1]hept-2-enes with short fluorocarbon segments were polymerized by ring-opening metathesis polymerization in THF at room temperature using Mo(CHCMe2Ph)(N-2,6-iPr2Ph)(OtBu)2 as the initiator. Although hydrocarbon and fluorocarbon segments as short as three methylenic units each induce smectic layering in the corresponding 2,5-bis{[4‘-(n-(perfluoroalkyl)alkoxy)benzoyl]oxy}toluene model compounds, the polymers require at least eight and three, or five and four methylenic units in the hydrocarbon and fluorocarbon segments, respectively, to organize into smectic layers; polymers with shorter hydrocarbon and/or fluorocarbon segments are nematic.