Synthesis, reactions and structure–activity relationships of 1-hydroxyspiro[2.5]cyclooct-4-en-3-ones: Illudin analogs with in vitro cytotoxic activity Original Research Article

1-Hydroxyspiro[2.5]cyclooct-4-en-3-ones—analogs of natural illudines—were prepared in good yields by cyclization of 1,3-dicarbonyl dianions or 1,3-bis-silyl enol ethers (‘masked dianions’) with 1,1-diacylcyclopropanes. Several spirocyclopropanes showed a significant antiproliferative activity against human leukemia HL60 cells in vitro. 1-Hydroxyspiro[2.5]cyclooct-4-en-3-ones represent highly reactive precursors of unstable spiro[5.2]cycloocta-4,7-dien-6-ones and reactions with a number of nucleophiles were studied.