Lewis, Frank, McCabe, Thomas and Grayson, David (2011) Preliminary investigations on novel camphor-derived chiral sulfones: completely stereoselective formation of tricyclic β-hydroxy sulfones from 8- and 10- functionalized camphor derivatives. Tetrahedron, 67 (39). pp. 7517-7528. ISSN 0040-4020
Full text not available from this repository. (Request a copy)Abstract
Some camphor-derived chiral allylic and benzylic sulfones in which the sulfonyl group is located at the C-10, C-9 or C-8 methyl groups of (+)-camphor were synthesized. The C-9 and C-8 substituted sulfones were obtained via Wagner-Meerwein rearrangements of the bicyclic camphor framework. On treatment with LDA, the C-10 and C-8 substituted sulfones cyclized with complete stereoselectivity, affording tricyclic β-hydroxysulfones whose relative configurations were determined by X-ray crystallography. Tricyclic sulfones 23 and 24 underwent both β-elimination and retro-aldol reactions on further exposure to base. Reduction of the carbonyl group of the C-10 substituted sulfones afforded exo-configured isobornyl sulfones with high stereoselectivity. Reaction of the lithiated isobornyl benzylsulfone 32 with benzaldehyde generated all four of the possible product diastereomers, of which three were isolated pure by chromatography. Attempted desulfonylation of these diastereomers failed to generate the desired optically active homobenzylic alcohols but the same sulfonyl carbanion trapping/desulfonylation sequence was successful in a model achiral series of compounds
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Sulfones, camphor, asymmetric synthesis, chiral auxiliary, carbanion |
| Subjects: | F100 Chemistry |
| Department: | Faculties > Health and Life Sciences > Applied Sciences |
| Depositing User: | Frank Lewis |
| Date Deposited: | 02 Jan 2013 11:03 |
| Last Modified: | 12 Oct 2019 18:26 |
| URI: | http://nrl.northumbria.ac.uk/id/eprint/10883 |
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