Expedient Pyrrolizidine Synthesis by Propargylsilane Addition to N-Acyliminium Ions followed by Gold-Catalyzed α-Allenyl Amide Cyclization

AC Breman, J Dijkink, JH van Maarseveen…

Index: Breman, Arjen C.; Dijkink, Jan; Van Maarseveen, Jan H.; Kinderman, Sape S.; Hiemstra, Henk Journal of Organic Chemistry, 2009 , vol. 74, # 16 p. 6327 - 6330

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Citation Number: 33

Abstract

A reaction sequence, involving the addition of (substituted) propargylsilanes to lactam- derived N-acyliminium ions followed by gold-catalyzed cyclization of the resulting α-allenyl amide, is applied in expedient syntheses of pyrrolizidine alkaloids heliotridine and ent- retronecine in five steps from (S)-malic acid.