1392115-75-1Relevant academic research and scientific papers
Z - And enantioselective ring-opening/cross-metathesis with enol ethers catalyzed by stereogenic-at-Ru carbenes: Reactivity, selectivity, and Curtin-Hammett kinetics
Khan, R. Kashif M.,O'Brien, Robert V.,Torker, Sebastian,Li, Bo,Hoveyda, Amir H.
, p. 12774 - 12779 (2012/09/05)
The first instances of Z- and enantioselective Ru-catalyzed olefin metathesis are presented. Ring-opening/cross-metathesis (ROCM) reactions of oxabicyclic alkenes and enol ethers and a phenyl vinyl sulfide are promoted by 0.5-5.0 mol % of enantiomerically pure stereogenic-at-Ru complexes with an aryloxy chelate tethered to the N-heterocyclic carbene. Products are formed efficiently and with exceptional enantioselectivity (>98:2 enantiomer ratio). Surprisingly, the enantioselective ROCM reactions proceed with high Z selectivity (up to 98% Z). Moreover, reactions proceed with the opposite sense of enantioselectivity versus aryl olefins, which afford E isomers exclusively. Preliminary DFT calculations in support of Curtin-Hammett kinetics as well as initial models that account for the stereoselectivity levels and trends are provided.
