Catalytic Ring Closing Metathesis of Dienynes: Construction of Fused Bicyclic [n.m.0] Rings
摘要:
Ruthenium carbene 1 (Cl-2(PCy(3))(2)Ru=CHCH=CPh(2)) mediates the efficient and selective conversion of acyclic dienynes to fused bicyclic [n.m.O] rings containing five-, six-, and seven-membered rings. Studies with various X-substituted acetylenes (X=H, alkyls, Ph, CO(2)Me, SnBu(3), TMS, Cl, Pr, I) suggest that the dienyne metathesis is sensitive not only to these substituents but also to the catalysts employed. Among the various metal alkylidenes examined, only the ruthenium catalyst 1 exhibited metathesis activity for a range of substrates. These observations further expand the scope of catalytic RCM for the construction of complex organic compounds.
Tandem Catalysis: The Sequential Mediation of Olefin Metathesis, Hydrogenation, and Hydrogen Transfer with Single-Component Ru Complexes
作者:Janis Louie、Christopher W. Bielawski、Robert H. Grubbs
DOI:10.1021/ja016431e
日期:2001.11.1
extensive use in olefin metathesis, it was also recently shown to be an effective precatalyst for mediating radical additions and hydrogenation reactions. We recently demonstrated all three reactions could be performed in tandem to afford well-defined block copolymers. Herein, we report that complex 1, or its more active derivative 2, is also useful in mediating a variety of other catalytic hydrogenation
Microwave‐Assisted Rhodium‐Complex‐Catalyzed Cascade Decarbonylation and Asymmetric Pauson–Khand‐Type Cyclizations
作者:Hang Wai Lee、Lai Na Lee、Albert S. C. Chan、Fuk Yee Kwong
DOI:10.1002/ejoc.200800272
日期:2008.7
Microwave-assisted Rh–diphosphane-complex-catalyzed dual catalysis is reported. This cooperative process provides [2+2+1] cycloadducts by sequential decarbonylation of aldehyde or formate and carbonylation of enynes within a short period of time. Various O-, N-, and C-tethered enynes were transformed into the corresponding products in good yields. The first enantioselective version of this microwave-accelerated
Chemodivergent Metathesis of Dienynes Catalyzed by Ruthenium-Indenylidene Complexes: An Experimental and Computational Study
作者:Hervé Clavier、Andrea Correa、Eduardo C. Escudero-Adán、Jordi Benet-Buchholz、Luigi Cavallo、Steven P. Nolan
DOI:10.1002/chem.200900976
日期:2009.10.5
study on the enyne metathesis reaction leading to the formation cyclic compounds using ruthenium–indenylidenecomplexes is presented. Several 1,11‐dien‐6‐ynes have been subjected to ruthenium metathesis cyclization by using ruthenium–indenylidenecomplexes bearing various phosphine and N‐heterocyclic carbene (NHC) ligands. Interestingly, for some substrates chemodivergent metathesis occurs and is a function
developed to perform olefin metathesis in roomtemperatureionicliquids (RTILs). High level of recyclability combined with a high reactivity were obtained in the ring-closing metathesis (RCM) of a variety of di- or tri-substituted and/or oxygen-containing dienes. Extremely low residual ruthenium levels were detected in the RCM products (average of 7.3 ppm per run). Several examples of olefin cross-metathesis
Liquid or supercritical carbon dioxide (scCO(2)) is a versatile reaction medium for ring-opening metathesis polymerization (ROMP) and ring-closing olefin metathesis (RCM) reactions using well-defined metal catalysts. The molybdenum alkylidene complex 1 and ruthenium carbenes 2 and 3 bearing PCy(3) or N-heterocyclic carbene ligands, respectively, can be used and are found to exhibit efficiency similar