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Iridium-Catalyzed Asymmetric Hydrogenation of Unfunctionalized, Trialkyl-Substituted Olefins

Wang, Aie and Fraga, Rui P. A. and Hörmann, Esther and Pfaltz, Andreas. (2011) Iridium-Catalyzed Asymmetric Hydrogenation of Unfunctionalized, Trialkyl-Substituted Olefins. Chemistry - An Asian Journal, 6 (2). pp. 599-606.

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Official URL: http://edoc.unibas.ch/dok/A5849076

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Abstract

Chiral iridium complexes with bicyclic pyridine-based N,P ligands have emerged as efficient catalysts for the enantioselective hydrogenation of unfunctionalized trialkyl-substituted olefins. Optimization of the reaction conditions by variation of the solvent, pressure, and temperature led to enantiomeric excesses of up to 99 %. Three pure alkenes, (E)-2-cyclohexyl-2-butene and (E)- and (Z)-3,4-dimethyl-2-pentene were converted into the corresponding chiral alkanes with 97 %, 94 %, and 93 % ee, respectively. Hydrogenation of the three C[DOUBLE BOND]C bonds of both α- and γ-tocotrienyl acetate led to α- and γ-tocopheryl acetate with very high diastereoselectivity. The same catalysts were successfully applied in the hydrogenation of trisubstituted alkenes with a carboxylic ester or a keto group in the γ position. This reaction was used as a key step in a highly enantioselective synthesis of the pheromone of the caddisfly Hesperophylax occidentalis. The hydrogenation of a structurally analogous allylic alcohol also gave high enantioselectivities.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Synthetische organische Chemie (Pfaltz)
UniBasel Contributors:Pfaltz, Andreas and Hörmann, Esther
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Wiley
ISSN:1861-4728
e-ISSN:1861-471X
Note:Publication type according to Uni Basel Research Database: Journal article
Identification Number:
Last Modified:10 Apr 2017 10:07
Deposited On:14 Sep 2012 07:01

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