Expedient Pyrrolizidine Synthesis by Propargylsilane Addition to<i>N</i>-Acyliminium Ions followed by Gold-Catalyzed α-Allenyl Amide Cyclization
作者:Arjen C. Breman、Jan Dijkink、Jan H. van Maarseveen、Sape S. Kinderman、Henk Hiemstra
DOI:10.1021/jo901393y
日期:2009.8.21
A reaction sequence, involving the addition of (substituted) propargylsilanes to lactam-derived N-acyliminiumions followed by gold-catalyzed cyclization of the resulting α-allenyl amide, is applied in expedient syntheses of pyrrolizidinealkaloids heliotridine and ent-retronecine in five steps from (S)-malic acid.