Item type:Thesis, Open Access

Asymmetrische 1,4-Additionen von Metallorganylen an einfach und zweifach ungesättigte Ketone und Imine

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2018-01-29

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Philipps-Universität Marburg
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Abstract

The asymmetric conjugate addition (ACA) of organometallic reagents to Michael acceptors is one of the most important reactions for enantioselective formation of carbon-carbon bonds. In the first part of this thesis, the substrate scope of the rhodium/BINAP-catalyzed 1,4-addition of alkenylzirconocenes to cyclic and acyclic enones – already investigated in my own master thesis – was extended, as well as the scope of transferable alkenyl nucleophiles. The inter¬mediate enolates were trapped as TMS enol ethers, or their TBDMS derivatives, respectively. A proof of concept for employing alkenyl titanates and alanates in the rhodium-catalyzed ACA was demonstrated. Furthermore, Grignard reagent-based aryl titanates were tested for the enantioselective transfer of potentially functionalized aryl nucleophiles. In the second part of the thesis, the synthesis of fluorinated cyclohexa-2,5-dieneimines and their application in copper/phosphoramidite ligand-catalyzed asymmetric 1,4-additions of dialkylzinc reagents was investigated. Having achieved an enantioselective access to cyclohex-2-eneimines, diastereoselective subsequent transformations of the latter were established. These include a second 1,4-addition step of diethylzinc using the same catalytic system, or phenylzinc chloride using the catalytic system rhodium/BINAP, or organocuprates, respectively. The intermediate enamides thus obtained were subjected to a final Noyori transfer hydrogenation step to yield cyclohexylamides in high overall yields. Further diastereoselective transformations of the cyclohex-2-eneimines, e.g. rhodium/BINAP-catalyzed 1,2-addition of phenylzinc chloride, reduction using sodium borohydride and hydrogenation, as well as cyanation and subsequent reduction to a primary amine were successfully achieved.

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Dates
Created: 2018Issued: 2018-01-29Updated: 2018-03-01
DOI
https://doi.org/10.17192/z2018.0087
Faculty
Fachbereich Chemie
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
rhodium1,4-Additioncatalysis1,4-additionchemistry and allied sciencescopper
DFG-subjects
KatalyseEnantiomereFluorEnoneChemieKupferRhodiumImine
DDC-Numbers
540
License
https://creativecommons.org/licenses/by-nc-nd/4.0/
URI
https://open.uni-marburg.de/handle/10.17192/z2018.0087
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Pfaff, Christopher Bernd: Asymmetrische 1,4-Additionen von Metallorganylen an einfach und zweifach ungesättigte Ketone und Imine. : Philipps-Universität Marburg 2018-01-29. DOI: https://doi.org/10.17192/z2018.0087.

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Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 - CC BY NC ND
Except where otherwised noted, this item's license is described as Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 - CC BY NC ND