Abstract
A new application of exo-2-oxazolidinone dienes in the regioselective synthesis of natural carbazoles, 6-methoxymurrayanine (6) and clausenine (7), is described. The regioselective cycloaddition of novel diene 10 to acrolein by Lewis acid catalysis provided adduct 12, which after aromatization gave benzoxazolone 14 as the key intermediate for the preparation of both carbazoles. A straightforward and efficient synthesis of 7 was carried out by a procedure with no isolation of intermediates, starting from 14 and went through a sequence of hydrogenation-hydrolysis-methylation and Pd-cyclization to give the desired carbazole 7 in high overall yield.
| Original language | English |
|---|---|
| Pages (from-to) | 1943-1948 |
| Number of pages | 6 |
| Journal | Synthesis (Germany) |
| Issue number | 13 |
| DOIs | |
| State | Published - 3 Jul 2007 |
Keywords
- 4,5-dimethylene-2-oxazolidinone dienes
- 6-methoxymurrayanine
- Carbazoles
- Clausenine
- Decarbonylation
- Diels-Alder reaction