Light- and Thermal-Activated Olefin Metathesis of Hindered Substrates
作者:Elisa Ivry、Alexander Frenklah、Yakov Ginzburg、Efrat Levin、Israel Goldberg、Sebastian Kozuch、N. Gabriel Lemcoff、Eyal Tzur
DOI:10.1021/acs.organomet.7b00677
日期:2018.1.22
metathesis reactions of tetra-substituted olefins were obtained by the S-chelated ruthenium precatalyst Tol-SCF3. Its reactivity in a series of benchmark olefin metathesis reactions was compared to previously reported Mes-SCF3 and a novel stericallycongested S-chelated complex, Dipp-SCF3. Tol-SCF3 is thus the first latent catalyst proven to be capable of promoting olefin metathesis of demanding substrates
An [(NHC)(NHC<sub>EWG</sub>)RuCl<sub>2</sub>(CHPh)] Complex for the Efficient Formation of Sterically Hindered Olefins by Ring-Closing Metathesis
作者:Tim Vorfalt、Steffen Leuthäußer、Herbert Plenio
DOI:10.1002/anie.200900935
日期:2009.6.29
NHC with EWGs for RCM: Ruthenium complexes with two N‐heterocyclic carbenes (NHCs), one of them substituted with electron‐withdrawing groups (EWGs), are highly efficient (pre)catalysts for the synthesis of tetrasubstitutedolefins and trisubstituted olefins by ring‐closing metathesis reactions (RCM, see scheme).
Highly Efficient Ruthenium Catalysts for the Formation of Tetrasubstituted Olefins via Ring-Closing Metathesis
作者:Ian C. Stewart、Thay Ung、Alexandre A. Pletnev、Jacob M. Berlin、Robert H. Grubbs、Yann Schrodi
DOI:10.1021/ol0705144
日期:2007.4.1
[reaction: see text] A series of ruthenium-based metathesis catalysts with N-heterocyclic carbene (NHC) ligands have been prepared in which the N-aryl groups have been changed from mesityl to mono-ortho-substituted phenyl (e.g., tolyl). These new catalysts offer an exceptional increase in activity for the formation of tetrasubstituted olefins via ring-closingmetathesis (RCM), while maintaining high
作者:Lindsay A. Batory、Christine E. McInnis、Jon T. Njardarson
DOI:10.1021/ja067073o
日期:2006.12.1
A novel copper-catalyzed vinyl oxirane ring expansion protocol has been developed. A wide range of vinyl oxiranes can be rearranged to 2,5-dihydrofurans in excellent yields in the presence of electrophilic copper(II) acetylacetonate catalysts. Regioisomeric vinyl oxiranes can be converted to a single dihydrofuran product using these conditions. This method uses low catalyst loadings (0.5-5 mol %), has good tolerance of substitution patterns, and can be done in the absence of solvent.