Z- and Enantioselective Ring-Opening/Cross-Metathesis with Enol Ethers Catalyzed by Stereogenic-at-Ru Carbenes: Reactivity, Selectivity, and Curtin–Hammett Kinetics
Citations Over TimeTop 10% of 2012 papers
Abstract
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.
Related Papers
- → Resolution/Deracemization of Chiral α-Amino Acids Using Resolving Reagents with Flexible Stereogenic Centers(2009)95 cited
- → Asymmetric Silaboration of Terminal Allenes Bearing α-Stereogenic Centers: Stereoselection Based on “Reagent Control”(2006)53 cited
- → Dibenzylamine substituted cyclotetraphosphazenes: Synthesis, characterization and their stereogenic properties(2018)5 cited
- → Synthesis of atropisomeric diamides with remotely related stereogenic axes by stereoselective additions to imines(1999)24 cited
- → 2.4 General Principles of Diastereoselective Reactions: Acyclic Control of Diastereoselectivity(2012)1 cited