Stereoselective Alcohol Silylation by Dehydrogenative Si-O Coupling: Scope, Limitations, and Mechanism of the Cu-H-Catalyzed Non-Enzymatic Kinetic Resolution with Silicon-Stereogenic Silanes
| Autor: | Gertrud Auer, Oliver Plefka, Betül Karatas, Christian Mück-Lichtenfeld, Stefan Grimme, Sebastian Rendler, Martin Oestreich, Roland Fröhlich |
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| Rok vydání: | 2008 |
| Předmět: |
Silicon
Silanes Silylation Stereochemistry Organic Chemistry Molecular Conformation Enantioselective synthesis Stereoisomerism General Chemistry Combinatorial chemistry Silane Catalysis Kinetic resolution Stereocenter Kinetics chemistry.chemical_compound chemistry Alcohols Quantum Theory Reactivity (chemistry) Racemization Copper |
| Zdroj: | Chemistry - A European Journal. 14:11512-11528 |
| ISSN: | 0947-6539 |
| Popis: | Ligand-stabilized copper(I)- hydride catalyzes the dehydrogenative Si-O coupling of alcohols and silanes— a process that was found to proceed without racemization at the silicon atom if asymmetrically substituted. The present investigation starts from this pivotal observation since silicon-stereo- genic silanes are thereby suitable for the reagent-controlled kinetic resolu- tion of racemic alcohols, in which asymmetry at the silicon atom enables discrimination of enantiomeric alco- hols. In this full account, we summarize our efforts to systematically examine this unusual strategy of diastereoselec- tive alcohol silylation. Ligand (suffi- cient reactivity with moderately elec- tron-rich monophosphines), silane (rea- sonable diastereocontrol with cyclic si- lanes having a distinct substitution pat- tern) as well as substrate identification (chelating donor as a requirement) are introductorily described. With these basic data at hand, the substrate scope was defined employing enantiomeri- cally enriched tert-butyl-substituted 1- silatetraline and highly reactive 1-si- laindane. The synthetic part is comple- mented by the determination of the stereochemical course at the silicon atom in the Si-O coupling step fol- lowed by its quantum-chemical analysis thus providing a solid mechanistic pic- ture of this remarkable transformation. |
| Databáze: | OpenAIRE |
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