Access to enantioenriched cyclic sulfones
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Authors
Schiele, Stefanie
Date
Type
thesis
Language
eng
Keyword
chiral cyclic sulfones, asymmetric oxidation, vanadium, Schiff base ligands
Alternative Title
Abstract
Chiral cyclic sulfones are valuable synthons and are present in biologically active compounds. Herein we report the first example of an enantioselective vanadium-catalyzed oxidation of racemic cyclic thioethers, using a chiral Schiff base ligand. Mild conditions, short reaction times, and the use of hydrogen peroxide as the oxidant afforded α-arylated cyclic sulfones in high to moderate enantiomeric excess. A range of molecules and precatalysts have been tested. The best results were obtained using a ligand prepared by condensation of 3,5-di-tert-butylsalicylaldehyde with (1R,2S)-1-methyl-valinol, which is then complexed with VO(acac)2. The vanadium precatalysts were characterized via 51V-NMR spectroscopy. In addition, 1H-NMR reaction monitoring provided evidence of kinetic resolution with further control experiments supporting this conclusion.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
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ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.