Spirocyclopropanes and -cyclobutanes are of considerable current interest, due to their pharmacological properties. For example, the illudins S and M represent cytotoxic constituents of the fungus Omphalotus illudens. 1 They possess a 1-hydroxyspiro[5.2]cyclooct-4-en-2-one structure. Synthetic analogues show a considerable anti-proliferative activity against human leukaemia HL 60 cells. 2 Spirocyclopropanes containing aromatic rings fused to the double bonds are present, for example, in the ...
![spiro[2,4-dihydrobenzo[h][1,5]benzodioxepine-3,1'-cyclobutane] Structure](https://image.chemsrc.com/caspic/059/65478-51-5.png)