Living Ring-Opening Metathesis Polymerization of 2,3-Difunctionalized- Norbornadienes by Mo(CH-t-Bu)(N-2,6-C(6)H(3)-i-Pr(2)(O-t-Bu)(2)
06 Aug 1990-Journal of the American Chemical Society (Defense Technical Information Center)-Vol. 112, Iss: 23, pp 8378-8387
TL;DR: Benzonorbornadiene and 2,3 bis(trifluoromethyl)norbornadienes can be polymerized by Mo(CH-t-Bu) in a well-behaved living manner to give essentially monodisperse homopolymers as mentioned in this paper.
Abstract: : Benzonorbornadiene 2,3-dicarbomethoxynorbornadiene and 2,3- bis(trifluoromethyl)norbornadiene can be polymerized by Mo(CH-t-Bu)(NAr)(O-t-Bu) 2(Mo(CH-t-Bu)) in a well-behaved living manner to give essentially monodisperse homopolymers. Two of the polymers and (especially) poly 5 are highly trans, and are believed to be tactic. The rate of polymerization is approximately thirty times faster at room temperature, a factor of approximately ten of which can be ascribed to the lower reactivity and the remainder to the lower reactivity relative to 7-Isopropylidene-2-3-dicarbomethoxynorbornadiene is not polymerized at all by Mo(CH-t-Bu), although it does react with Mo(CH-t-Bu). An X-ray structure shows it to be a pseudo-tetrhedral species containing a syn alkylidene ligand (substituent pointing toward the imido nitrogen atom).
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TL;DR: The discussion includes an analysis of trends in catalyst activity, a description of catalysts coordinated with N-heterocyclic carbene ligands, and an overview of ongoing work to improve the activity, stability, and selectivity of this family of L2X2Ru=CHR complexes.
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TL;DR: Some recent examples where dynamic covalent chemistry has been demonstrated are shown to emphasise the basic concepts of this area of science.
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TL;DR: The fascinating story of olefin (or alkene) metathesis began almost five decades ago, when Anderson and Merckling reported the first carbon-carbon double-bond rearrangement reaction in the titanium-catalyzed polymerization of norbornene.
Abstract: The fascinating story of olefin (or alkene) metathesis (eq
1) began almost five decades ago, when Anderson and
Merckling reported the first carbon-carbon double-bond
rearrangement reaction in the titanium-catalyzed polymerization of norbornene. Nine years later, Banks and Bailey reported “a new disproportionation reaction . . . in which olefins are converted to homologues of shorter and longer carbon chains...”. In 1967, Calderon and co-workers named this metal-catalyzed redistribution of carbon-carbon double bonds olefin metathesis, from the Greek word “μeτάθeση”, which means change of position. These contributions have since served as the foundation for an amazing research field, and olefin metathesis currently represents a powerful transformation in chemical synthesis, attracting a vast amount of interest both in industry and academia.
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TL;DR: Application of this model has allowed for the prediction and development of selective cross metathesis reactions, culminating in unprecedented three-component intermolecular cross metAthesis reactions.
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