Haindl, Michael H. and Schmid, Markus B. and Zeitler, Kirsten and Gschwind, Ruth M. (2012) What is your actual catalyst? TMS cleavage rates of diarylprolinol silyl ethers studied by in situ NMR. RSC ADVANCES, 2 (14). pp. 5941-5943. ISSN 2046-2069,
Full text not available from this repository. (Request a copy)Abstract
Diarylprolinol silyl ethers are excellent and broadly applicable organocatalysts for various enamine and iminium-type synthetic transformations. However, their undesired degradation to the corresponding diarylprolinols and the subsequent formation of oxazolidines during reaction with aldehydes may significantly affect their catalytic performance. Therefore, in situ NMR was used to examine the TMS cleavage rate of diarylprolinol silyl ethers as a function of solvent properties, acidic/basic additives and the presence of water. Highly polar solvents with strong hydrogen bond acceptor properties and especially moderate acidic additives with pK(a) (DMSO) values around 10 accelerate the deprotection significantly, whereas basic and highly acidic additives are not detrimental. Additional mechanistic studies reveal that the substitution reaction takes places at the silicon atom.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ORGANOCATALYTIC DOMINO REACTIONS; DIMETHYL-SULFOXIDE; ALPHA,BETA-UNSATURATED ALDEHYDES; ASYMMETRIC-SYNTHESIS; ENAMINE CARBOXYLATES; MICHAEL ADDITION; PROLINOL; ACETONITRILE; DERIVATIVES; EPOXIDATION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind Chemistry and Pharmacy > Institut für Organische Chemie > Alumni or Retired Professors > Arbeitskreis Dr. Kirsten Zeitler |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 25 May 2020 05:33 |
| Last Modified: | 25 May 2020 05:33 |
| URI: | https://pred.uni-regensburg.de/id/eprint/19471 |
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