Olefin metathesis of cyclohexene

Patton, Penelope A.; Lillya, C. Peter; McCarthy, Thomas J.

doi:10.1021/ma00158a056

Cited by 47 publications

(46 citation statements)

References 2 publications

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“…In the case of a-methylstyrene and cyclohexene, they were completely absent. This is most likely due to the steric constraints encountered in the formation of a tetrasubstituted olefin from a-methylstyrene or to the adverse thermodynamics for the ring-opening of cyclohexene [25]. Unlike the other olefinic substrates investigated so far, norbornene was not cyclopropanated by ethyl diazoacetate in the presence of complex 2 (Table 3).…”

Section: Resultsmentioning

confidence: 96%

Ruthenium–arene catalysts bearing N-heterocyclic carbene ligands for olefin cyclopropanation and metathesis

et al. 2015

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Ruthenium-arene complexes bearing N-heterocyclic carbene (NHC) ligands with the generic formula [RuCl 2 (p-cymene)(NHC)] are efficient catalyst precursors for the cyclopropanation of activated olefins with ethyl diazoacetate, and the cis/trans diastereoselectivity of the reaction markedly depends on the steric bulk of the NHC. The procedure was successfully applied to styrene, amethylstyrene, and various other styrenic derivatives bearing electron-withdrawing or donating substituents on their aromatic rings. The reaction of unactivated internal or terminal alkenes was more sluggish, and the use of norbornene as a substrate afforded only olefin metathesis. Further investigation of the ring-opening metathesis polymerization of this strained cycloolefin in the presence of trimethylsilyldiazomethane led to high molecular weight polynorbornene whose microstructure was not significantly affected by the choice of the NHC ancillary ligand. Graphical abstract

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Section: Resultsmentioning

confidence: 96%

Ruthenium–arene catalysts bearing N-heterocyclic carbene ligands for olefin cyclopropanation and metathesis

et al. 2015

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“…Since chloroform-d boils at 60. 9 C in ambient conditions, the operational temperature range was limited to 50 C to prevent any changes in the reactant concentration which could be caused by evaporation.…”

Section: Well-defined Ruthenium Metathesis Catalystsmentioning

confidence: 99%

“…However, if the deformation energy of cycle is low, the contribution of the entropy factor into the Gibbs energy becomes more significant in comparison with a smaller enthalpy factor. In this case, the entropy factor must be properly reduced in order to implement the direct process by increasing the monomer concentration or decreasing the temperature of the process [9].…”

Section: Introductionmentioning

confidence: 99%

Ring Opening Metathesis Polymerization

Lyapkov¹,

Kiselev²,

Bozhenkova³

et al. 2018

Recent Research in Polymerization

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In recent years, the olefins metathesis has established itself as a powerful tool for carboncarbon bonds forming and has found numerous applications in polymer chemistry. One of the important directions of metathesis is the polymerization with cycle opening. A study of new ruthenium catalysts, resistant to the many functional groups effects, has showed the possibility of synthesizing functionalized polymers with unique properties. In this chapter, reactivity and activation parameters of eight different norbornene dicarboxylic acid alkyl esters in the presence of a Hoveyda-Grubbs II catalyst for the ring opening metathesis polymerization were determined by 1 H NMR analysis in-situ. The molecules of esters differ in the aliphatic radical structure and the location of the substituent groups. Kinetic studies have shown that effective polymerization constants and activation parameters strongly depend on the monomer structure. It is shown that the elongation of the aliphatic radical does not significantly affect the reactivity, but significantly changes the activation parameters. The branching of the aliphatic radical significantly affects both the reactivity of the corresponding ester and the activation parameters of the polymerization. The position of the substituents in the norbornene ring of the ester also has a significant effect on the activation parameters of metathesis polymerization.

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“…As illustrated in Scheme 3, BEB sequences can readily yield the six membered cyclohexene ring by back-biting. In contrast to other rings, the latter accumulates in the reacting medium since it is resistant to ROMP [26]. The number of cyclohexene molecules formed by PEB chain and by initial BEB sequence are indicated in Table 2.…”

Section: Depolymerization In Absence Of a Ctamentioning

confidence: 99%