Solid state auto-inversion of C-centrochirality: enantioselective total synthesis of furocarbazolones (-)-epi-claulansine D and (-)-claulansine D and pyranocarbazolone (+)-epi-claulansine C
| Title | Solid state auto-inversion of C-centrochirality: enantioselective total synthesis of furocarbazolones (-)-epi-claulansine D and (-)-claulansine D and pyranocarbazolone (+)-epi-claulansine C |
| Publication Type | Journal Article |
| Year of Publication | 2018 |
| Authors | Markad, SB, Argade, NP |
| Journal | Journal of Organic Chemistry |
| Volume | 83 |
| Issue | 1 |
| Pagination | 382-387 |
| Date Published | JAN |
| Type of Article | Article |
| ISSN | 0022-3263 |
| Abstract | Starting from dimethyl (E)-2-{[(1-tert-butoxycarbonyl)-1H-indol-3-yl]methylene}succinate and (R)-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbaldehyde, facile synthesis of (-)-epi-claulansine D was accomplished via condensation and two intramolecular cyclizations. The (-)-epi-claulansine D in the solid state exists in a metastable form, and after an induction period of 30-90 days, it underwent complete epimerization to exclusively deliver the desired natural product (-)-claulansine D in quantitative yield. The witnessed inversion of C-centrochirality in the solid state is conceptually novel and takes place for relatively higher crystal stability reasons. Base-catalyzed ring expansion of both (+/-)/(-)-epi-claulansine D and (+/-)/(-)-claulansine D resulted in (+/-)/(+)-epi-claulansine C in very good yields. |
| DOI | 10.1021/acs.joc.7b02773 |
| Type of Journal (Indian or Foreign) | Foreign |
| Impact Factor (IF) | 4.849 |
