Abstract
Novel radical cyclisation reactions, mediated by tributyltin hydride, samarium(II) iodide or manganese(III) acetate, have been explored to form tri- and tetra-cyclic ring systems related to the Amaryllidaceae or Erythrina family of alkaloids. Haloethanamide precursors possessing a cyclohexenone ring have been shown to form octahydroindolones, and erythrinane-type systems can be formed from precursors bearing unsaturated side-chains in tandem cyclisations. An octahydroindolone has been converted to the ring skeleton of gamma-lycorane using samarium(II) iodide while reaction with manganese(III) acetate has been shown to yield a novel tetracyclic ring system bearing a 7-membered ring. Finally, a new tandem cyclisation of a cyclohexenone aryl halide has been shown to provide a quick approach to a 5,5,6,6-tetracycle related to erythrinane natural products. (C) 2000 Elsevier Science Ltd. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 7217-7228 |
| Number of pages | 12 |
| Journal | Tetrahedron |
| Volume | 56 |
| Issue number | 37 |
| Publication status | Published - 8 Sept 2000 |
Keywords
- radicals and radical reactions
- cyclisation
- alkaloids
- enamides
- GAMMA-LYCORANE
- CYCLIZATIONS
- KETONES