Norbornene

About: Norbornene is a(n) research topic. Over the lifetime, 5628 publication(s) have been published within this topic receiving 104495 citation(s). The topic is also known as: norbornylene & norcamphene.

Synthesis and Applications of RuCl2(CHR‘)(PR3)2: The Influence of the Alkylidene Moiety on Metathesis Activity

Abstract: The reactions of RuCl2(PPh3)3 with a number of diazoalkanes were surveyed, and alkylidene transfer to give RuCl2(CHR)(PPh3)2 (R = Me (1), Et (2)) and RuCl2(CH-p-C6H4X)(PPh3)2 (X = H (3), NMe2 (4), OMe (5), Me (6), F (7), Cl (8), NO2 (9)) was observed for alkyl diazoalkanes RCHN2 and various para-substituted aryl diazoalkanes p-C6H4XCHN2. Kinetic studies on the living ring-opening metathesis polymerization (ROMP) of norbornene using complexes 3−9 as catalysts have shown that initiation is in all cases faster than propagation (ki/kp = 9 for 3) and that the electronic effect of X on the metathesis activity of 3−9 is relatively small. Phosphine exchange in 3−9 with tricyclohexylphosphine leads to RuCl2(CH-p-C6H4X)(PCy3)2 10−16, which are efficient catalysts for ROMP of cyclooctene (PDI = 1.51−1.63) and 1,5-cyclooctadiene (PDI = 1.56−1.67). The crystal structure of RuCl2(CH-p-C6H4Cl)(PCy3)2 (15) indicated a distorted square-pyramidal geometry, in which the two phosphines are trans to each other, and the alkyli...

Ruthenium-based heterocyclic carbene-coordinated olefin metathesis catalysts.

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.

Ring-opening metathesis polymerization (ROMP) of norbornene by a Group VIII carbene complex in protic media

Abstract: During the past two decades, intense research efforts have enabled an in-depth understanding of the olefin metathesis reaction as catalyzed by early transition metal complexes. In contrast, the nature of the intermediates and the reaction mechanism for group VIII transition metal metathesis catalysts remain elusive. Such knowledge is important in view of the promise group VIII metals show in polymerizing a wide variety of functionalized cyclic olefins in protic solvents. Highly active late transition metal catalysts should also open the way to the metathesis of functionalized acyclic olefins. Previous studies in our group have focused on the chemistry of highly active, functional-group-tolerant catalysts prepared from aquoruthenium(II) olefin complexes. In these systems, characterization of the catalytic intermediates is difficult due to their very low concentrations and high activity in the reaction mixtures. Although it is reasonable to assume that the active species are ruthenacyclobutanes and ruthenium carbenes (ruthenaolefins), the oxidation state and ligation of these intermediates are not known. Furthermore, the discrete ruthenium carbene complexes that have been isolated to date do not exhibit both metathesis activity and stability to protic/aqueous solvents. We report here the reaction of an Ru(II) complex with a strained olefin to produce a carbene species that polymerizes norbornene in organic media both in the absence and presence of protic/aqueous solvents. In both solvent systems, a stable propagating carbene complex can be observed throughout the course of the polymerization, as has been previously found with titanium, tantalum, tungsten, molybdenum, and ruthenium complexes.

Olefin metathesis and metathesis polymerization

Abstract: Preface. Abbreviations. Introduction: The Olefin Metathesis Reaction. Brief History. The Metal Carbene Mechanism. Equilibria and Stereoselectivity. Survey of Catalyst Systems: Group IV. Group V. GroupVI. Group VII. Group VIII. Photochemically Activated Catalysts. The Metal Carbene/Metallacyclobutane Mechanism: Evidence from Cross-Metathesis Reactions. Evidence from the Stereochemistry of Metathesis of Internal Olefins. Evidence from Ring-Opening Metathesis Polymerization (ROMP). Evidence from the reactions of Well-Defined Metal Carbene Complexes. Evidence from the Reactions of Metallacyclobutane Complexes. Evidence of Initiating Species in Systems with Non-Carbene Catalysts. Theoretical Treatments. Related Reactions: [2+2] Reactions Between Compounds Containing Multiple Bonds. Relationship to Ziegler-Natta Polymerization. Involvement of Three-Membered Ring Compounds in Metathesis Reactions. Ethene and Terminal Alkenes: Ethene. Propene. But-1-ene and its Derivatives. Pent-1-ene and its Derivatives. Hex-1-ene and its Derivatives. Higher Acyclic Terminal Alkenes. Acyclic Disubstituted and Trisubstituted Ethenes. Cis/trans Isomerization. Pent-2-ene and 4-Substituted Derivatives. Hex-2-ene and 4-Methylhex-2-ene.Hept-2-ene and Hept-3-ene. Higher Acyclic Internal Olefins. Stereoselectivity in the Metathesis of Acyclic Olefins. 1,1-Disubstituted Olefins. Trisubstituted Ethenes. Acyclic Functionalized Alkenes: Esters. Other Carbonyl-Containing Compounds. Ethers. Amines. Nitriles. Chlorides and Bromides. Sulfides and Sulfonates. Silancs and Germanes. Phospanes. Acyclic Dienes: Double Bonds Linked only by C Atoms. Double Bonds Linked by C and Si, Ge orSn Atoms. Double Bonds Linked by C and N Atoms. Double Bonds Linked by C, Si, and O Atoms. Divinylferrocene. Some Further Applications in Organic Synthesis. Copolymers by Metathesis Condensation. Cross-Metathesis Between Acyclic Compounds: Ethene.Propene. Butenes. Pentenes. Hexenes. Higher Olefins. Functionalized Olefins. Acetylenes: Metathesis Reactions Involving Total Cleavage of the C=C bond. Metathesis Reactions Involving Cleavage of Two of the thress C=C Bonds. Metathesis Reactions of Enynes and Dienynes. Other Metathesis Routes to Polyacetylenes. Ring-Opening Metathesis Polymerization: General Aspects: Thermodynamic Aspects. Efficiency of Initiation. The Use of Chain-Transfer Agents. Molecular Weight Distributions. Polymer Micostructure. Monocyclic Alkenes and Polyenes: Four-Membered Rings. Five-Membered Rings. Six-Membered Rings. Seven-Membered Rings. Eight-Membered Rings. Nine-Membered Rings. Ten-Membered Rings. Twelve-Membered and Other Rings. Polycyclic Alkenes: Monomers Containing a Fused Cyclobutene Ring. Monomers Containing a Fused Cyclopentene Ring and One Double Bond. Monomers Containing a Fused Cyclopentene Ring and More than One Double Bond. Bicyclo[2.2.1] Compounds Containing Heteroatoms in the Ring System. Other Bicyclic Compounds. Copolymers of Cycloalkenes: Direct Metathesis Copolymerization. Cyclic Co-Oligomers. Block Copolymers by Sequential Addition of Monomers to Living Systems. Block Copolymers by Modification of Homopolymers. Comb and GraftCopolymers. Copolymers by ROMP in Conjunction with Radical Reactions. Cross-Metathesis Between Cyclic and Acyclic Olefins: End-Groups and Telomers. Dependence of Molecular Weight on [M 2]/[M 1]. Kinetic Data. Degradation of UnsaturatedPolymers by Metathesis: Degradation by Intramolecular Metathesis. Applications of the Olefin Metathesis Reaction: The Phillips Triolefin Process. The Neohexene Process. The Shell Higher Olefins Process. Other Multistage Processes Involving Metathesis. The Isoamylene Process. (Circle around alpha and omega) ((-Diolefins. trans-Poly(1-Pentenylene). trans-Poly(1-octenylene). Polymers of Norhornene. Polymers of Norbornene Derivatives. Miscellaneous. Bibliography. Subject Index.

Aerobic epoxidation of olefins with ruthenium porphyrin catalysts

Abstract: Le dioxo(tetramesitylporphyrinato) ruthenium(VI) catalyse l'epoxydation des olefines (cyclooctene, cis- et trans-β-methylstyrene, norbornene) a temperature et pression ambiantes