| Autor: |
Ortiz E; Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States., Shezaf JZ; Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States., Chang YH; Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States., Gonçalves TP; KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia., Huang KW; KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia., Krische MJ; Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States. |
| Abstrakt: |
Crystallographic characterization of RuX(CO)(η 3 -C 3 H 5 )(JOSIPHOS), where X = Cl, Br, or I, reveals a halide-dependent diastereomeric preference that defines metal-centered stereogenicity and, therefrom, the enantioselectivity of C-C coupling in ruthenium-catalyzed anti -diastereo- and enantioselective C-C couplings of primary alcohols with 1-aryl-1-propynes to form products of carbonyl anti -(α-aryl)allylation. Computational studies reveal that a non-classical hydrogen bond between iodide and the aldehyde formyl CH bond stabilizes the favored transition state for carbonyl addition. An improved catalytic system enabling previously unattainable transformations was developed that employs an iodide-containing precatalyst, RuI(CO) 3 (η 3 -C 3 H 5 ), in combination with trifluoroethanol, as illustrated by the first enantioselective ruthenium-catalyzed C-C couplings of ethanol to form higher alcohols. |
