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| Content Provider | PubMed Central |
|---|---|
| Author | Webber, Peter Krische, Michael J. |
| Abstract | Concise stereoselective syntheses of (±)-quinine and (±)-7-hydroxyquinine are achieved using a catalytic enone cycloallylation that combines the nucleophilic features of the Morita-Baylis-Hillman reaction and the electrophilic features of the Tsuji-Trost reaction. Cyclization of enone-allyl carbonate 11 delivers the product of cycloallylation 13 in 68% yield. Diastereoselective conjugate reduction of the enone 13 (>20:1 dr) followed by exchange of N-protecting groups provides the saturated N-Boc-protected methyl ketone 19, which upon aldol dehydration provides quinoline containing enone 15, possessing all carbon atoms of quinine. Exposure of ketone 15 to L-selectride enables diastereoselective carbonyl reduction (>20:1 dr) to furnish the allylic alcohol 16. Stereoselective hydroxyl-directed epoxidation using an oxovanadium catalyst modified by N-hydroxy-N-Me-pivalamide delivers epoxide 17 (17:1 dr). Cyclization of the resulting amine-epoxide 17 provides (±)-7-hydroxyquinine in 13 steps and 11% overall yield from aminoacetaldehyde diethyl acetal. Notably, highly stereoselective formation of five contiguous stereocenters is achieved through a series of 1,2-asymmetric induction events. A formal synthesis of (±)-quinine is achieved upon deoxygenation of the N-Cbz-protected allylic acetate 22 to provide olefin 23, which previously has been converted to quinine. Thus, (±)-quinine is accessible in 16 steps and 4% overall yield from commercial aminoacetaldehyde diethyl acetal, making this route the most concise approach to quinine, to date. |
| Related Links | http://dx.doi.org/10.1021/jo802165k |
| Ending Page | 9387 |
| Page Count | 9 |
| Starting Page | 9379 |
| File Format | |
| ISSN | 00223263 |
| e-ISSN | 15206904 |
| Journal | The Journal of organic chemistry |
| Issue Number | 23 |
| Volume Number | 73 |
| Language | English |
| Publisher Date | 2008-12-05 |
| Access Restriction | Open |
| Subject Keyword | Organic Chemistry Research in Higher Education |
| Content Type | Text |
| Resource Type | Article |
| Subject | Organic Chemistry |
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