Z- and Enantioselective Ring-Opening/Cross-Metathesis with Enol Ethers Catalyzed by Stereogenic-at-Ru Carbenes: Reactivity, Selectivity, and Curtin–Hammett Kinetics

Autor:	Sebastian Torker, R. Kashif M. Khan, Robert V. O’Brien, Amir H. Hoveyda, Bo Li
Rok vydání:	2012
Předmět:	Stereochemistry Chemistry Aryl Enantioselective synthesis General Chemistry Metathesis Biochemistry Enol Catalysis Stereocenter chemistry.chemical_compound Colloid and Surface Chemistry Stereoselectivity Selectivity Carbene
Zdroj:	Journal of the American Chemical Society. 134:12774-12779
ISSN:	1520-5126 0002-7863
Popis:	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.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5b0548f5be78124a30309b91743fab3c https://doi.org/10.1021/ja304827a Zobrazit plný text záznamu