The oxoprotoberberine alkaloids 1a-d have been synthesized efficiently from the enamide derivatives 2a-d by a radical-initiated cyclization reaction utilizing n-Bu3SnH/AIBN and CuCl. The enamide derivatives 2a-d were prepared from phenylethylamine analogues 5a-b, followed by acylation with acetic anhydride, Bischler-Napieralski cyclization with POCl3 and benzoylation with the corresponding bromobenzoyl chloride, respectively.
All Science Journal Classification (ASJC) codes
- Drug Discovery
- Organic Chemistry