Radical-initiated cyclization as a key step for the synthesis of oxoprotoberberine alkaloids
作者:Chih-Shone Lee、Tsung-Ching Yu、Jian-Wen Luo、Yen-Yao Cheng、Che-Ping Chuang
DOI:10.1016/j.tetlet.2009.05.095
日期:2009.8
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. (C) 2009 Elsevier Ltd. All rights reserved.