摘要:
The invention pertains to the use of Group 8 transition metal carbene complexes as catalysts for olefin cross-metathesis reactions. In particular, ruthenium and osmium alkylidene complexes substituted with an N-heterocyclic carbene ligand are used to catalyze cross-metathesis reactions to provide a variety of substituted and functionalized olefins, including phosphonate-substituted olefins, directly halogenated olefins, 1,1,2-trisubstituted olefins, and quaternary allylic olefins. The invention further provides a method for creating functional diversity using the aforementioned complexes to catalyze cross-metathesis reactions of a first olefinic reactant, which may or may not be substituted with a functional group, with each of a plurality of different olefinic reactants, which may or may not be substituted with functional groups, to give a plurality of structurally distinct olefinic products. The methodology of the invention is also useful in facilitating the stereoselective synthesis of 1,2-disubstituted olefins in the cis configuration.
摘要:
The invention is directed to the cross-metathesis and ring-closing metathesis reactions between geminal disubstituted olefins and terminal olefins, wherein the reaction employs a Ruthenium or Osmium metal carbene complex. Specifically, the invention relates to the synthesis of &agr;-functionalized or unfunctionalized olefins via intermolecular cross-metathesis and intramolecular ring-closing metathesis using a ruthenium alkylidene complex. The catalysts preferably used in the invention are of the general formula wherein: M is ruthenium or osmium; X and X1 are each independently an anionic ligand; L is a neutral electron donor ligand; and, R, R1R6, R7, R8, and R9 are each independently hydrogen or a substituent selected from the group consisting of C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl and C1-C20 alkylsulfinyl.
摘要:
A catalytic method is provided for a ring-opening cross-metathesis reaction between a cycloolefinic substrate and a second olefinic reactant, wherein the catalyst used is a transition metal alkylidene complex substituted with an N-heterocyclic carbene ligand. The substrates are selected so that the rate of the cross-metathesis reaction of the second olefinic reactant, kCM, is greater than or equal to the rate of the ring-opening metathesis reaction, kRO. In this way, the predominant ROCM product is a monomer, dimer, and/or oligomer, but not a polymer. The invention additionally provides for selective production of an end-differentiated olefinic product, using trisubstituted cycloolefins as substrates and/or a subsequent cross-metathesis reaction following an initial ROCM step. The cycloolefinic substrates include low-strain olefins such as cyclohexene as well as higher strain olefins such as cyclooctene.
摘要:
This invention relates generally to synthetic procedures that include the step of ring-opening metathesis of cyclic olefins and reaction with an acyclic diene co-reactant to produce olefin macrocycles by ring expansion, or alternatively. The ring expansion of the cyclic olefin is provided by three types of sequential olefin metathesis (ring-opening, cross, and ring-closing olefin metathesis). More particularly, the invention pertains to synthesis of olefin macrocycles via olefin metathesis reactions using a Group 8 transition metal complex as the metathesis catalyst. Macrocycles provided herein have a variety of uses in the pharmaceutical, biomedical, organic synthesis and chemical industries, such as the production of crown ethers that are useful as metal complexing species.
摘要:
This invention relates generally to synthetic procedures that include the step of ring-opening metathesis of cyclic olefins and reaction with an acyclic diene co-reactant to produce regularly repeating A,B-alternating olefin polymers. The A,B-alternating polymers are produced by varying reaction conditions and/or reactant proportions and using only two types of olefin metathesis (ring-opening and cross) to provide regularly repeating ABAB . . . etc. polymers via ring-opening metathesis polymerization (ROMP). More particularly, the invention pertains to synthesis of A,B-alternating olefin polymers via olefin metathesis reactions using a Group 8 transition metal complex as the metathesis catalyst. Polymers provided herein have utility in a variety of fields, including not only polymer chemistry per se, but also in the pharmaceutical, biomedical, and packaging industries where the structure and properties of polymers need to be tightly controlled.