Chemistry of pyrrolizinones. Part 1. Reactions of pyrrolizin-3-ones with electrophiles: synthesis of 3, 8-didehydroheliotridin-5-one 1

H McNab, C Thornley

Index: McNab, Hamish; Thornley, Craig Journal of the Chemical Society, Perkin Transactions 1, 2000 , # 21 p. 3584 - 3591

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Citation Number: 13

Abstract

The reaction of pyrrolizin-3-one 1 with dry hydrogen chloride gives the 1-chloro-1, 2-dihydro derivative 8 (93%) by electrophilic addition. The halogen of 8 is readily displaced by O- nucleophiles to give 6, 9 or 10 in 87–100% yield, and this strategy has been employed in a short synthesis of the necine base didehydroheliotridin-5-one 4. Pyrrolizinone 1 can be brominated by N-bromosuccinimide in the presence of nucleophiles to give 20 or 21, or ...