New synthetic routes to 3-ethylidene-2′,4-6 trimethylgris-2′-en-4′-one.

3-Ethylidene-2′,4,6-trimethylgris-2′-en-4′-one has been synthesized by two alternative routes in the proof of the spiran nature of the compounds IV (R  COOC2H5 and R H) derived from the cyclization of diketobenzofurans (V, R  COOC2H5 and R  H).