Synthetic photochemistry. A synthesis of the carbon skeleton found in taylorione from Mylia taylorii, using the di-π-methane rearrangement

Abstract

Synthetic routes to the E- and Z-cyclopentenones (20) and (25), which incorporate photosensitive 1,4-diene systems, are described. Irradiation of the E-cyclopentenone (20) is shown to result in efficient regiospecific di-π-methane rearrangement (>70%) to the vinylcyclopropane (26), which is then converted into trans-deoxytaylorione (28). Irradiation of the corresponding Z-cyclopentenone (25) also leads to (26), presumably by way of the E-cyclopentenone (20), produced by Z—E photoisomerisation.