Synthesis, Fe(II)-induced degradation, and antimalarial activities of 1,5-diaryl-6,7-dioxabicyclo[3.2.2]nonanes: direct evidence for nucleophilic O-1,2-aryl shifts
摘要:
1,5-Diaryt-6.7-dioxabicyclo[3.2.2]nonanes 1a-d (1a: Ar=p-FC6H4, 1b: Ar=Ph. 1e: Ar=p-MeC6H4. 1d: Ar=pMeOC(6)H(4)) were prepared by a modified method of photo-electron transfer oxygenation. and the reactions of 1 with FeBr2 were investigated under various conditions. The Fe(Il)-induced degradation of 1 afforded various rearrangement products and fragmentation products through competitive single electron transfer (SET) and Lewis acid pathways. Direct evidence for the O-1,2-aryl shift was obtained by the isolation of rearrangement products. 1-aryloxy-5-aryl-8-oxabicyclo[3.2.1]octanes 8. The degradation mechanism was proposed and the in vitro antimalarial activities were also evaluated. (C) 2002 Elsevier Science Ltd. All rights reserved.