Topic
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.
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82 citations
TL;DR: The enantioselective [2 + 2] cycloaddition of alkynes possessing an ester functionality and norbornene derivatives proceeded efficiently using a chiral rhodium catalyst.
82 citations
TL;DR: Random copolymers made by living ring-opening metathesis polymerization of norbornene monomers containing either the elastin peptide sequence -(VPGVG)- or pentaethylene glycol exhibit a lower critical solution temperature (LCST).
Abstract: Random copolymers made by living ring-opening metathesis polymerization of norbornene monomers containing either the elastin peptide sequence -(VPGVG)- or pentaethylene glycol (see scheme; Mes=mesityl, pyr=pyridine) exhibit a lower critical solution temperature (LCST). The LCST can be easily modified by varying the ratio of the co-monomers in the polymer feed.
82 citations
TL;DR: Nickel and palladium complexes with α-dioxime ligands dimethylglyoxime, diphenyl glyoxime and 1,2-cyclohexanedioxime represent six new precatalysts for the polymerization of norbornene that can be activated with methylaluminoxane (MAO), the organo-Lewis acid tris(pentafluorophenyl)borane [B(C6F5)3], and triethylaluminum (TEA) AlEt3] as mentioned in this paper.
Abstract: Nickel(II) and palladium(II) complexes with α-dioxime ligands dimethylglyoxime, diphenylglyoxime, and 1,2-cyclohexanedionedioxime represent six new precatalysts for the polymerization of norbornene that can be activated with methylaluminoxane (MAO), the organo-Lewis acid tris(pentafluorophenyl)borane [B(C6F5)3], and triethylaluminum (TEA) AlEt3. The palladium but not the nickel precatalysts could also be activated by B(C6F5)3 alone, whereas two of the three nickel precatalysts but none of the palladium systems are somewhat active with only TEA as a cocatalyst. It was possible to achieve very high polymerization activities up to 3.2 · 107 gpolymer/molmetal · h. With the system B(C6F5)3/AlEt3, the activation process can be formulated as the following two-step reaction: (1) B(C6F5)3 and TEA lead to an aryl/alkyl group exchange and result in the formation of Al(C6F5)nEt3−n and B(C6F5)3−nEtn; and (2) Al(C6F5)nEt3−n will then react with the precatalysts to form the active species for the polymerization of norbornene. Variation of the B:Al ratio shows that Al(C6F5)Et2 is sufficient for high activation. Gel permeation chromatography indicated that it was possible to control the molar mass of poly(norbornene)s by TEA or 1-dodecene as chain-transfer agents; the molar mass can be varied in the number-average molecular weight range from 2 · 103 to 9 · 105 g · mol−1. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3604–3614, 2002
81 citations
TL;DR: The first nickel(0)-catalyzed [2 + 2 + 1] carbonylative cycloaddition reaction of imines and alkynes or norbornene has been achieved by employing phenyl formate as a CO source.
Abstract: The first nickel(0)-catalyzed [2 + 2 + 1] carbonylative cycloaddition reaction of imines and alkynes or norbornene has been achieved by employing phenyl formate as a CO source. With this method, a variety of N-benzenesulfonyl, -tosyl, and -phosphoryl-substituted γ-lactams can be prepared in good to high yields.
81 citations