Synthetic studies towards oxylipins: total synthesis of Constanolactones A and B

The sequential addition of functionalised chains onto a 1,2-diformylcyclopropane synthon provides rapid access to cyclopropyl oxylipins, as demonstrated here by the total synthesis of Constanolactones A–B. These eicosanoids of marine origin have been prepared in five steps, first by the regioselective γ-addition of 1-trialkylsilyloxy-1-ethoxybutadiene to (1S,2S)-1-formyl-2-(thexyldimethylsilyloxymethyl)cyclopropane, then, after functional group modifications, addition of a (1E,3S,5Z)-3-hydroxyundeca-1,5-dienyl organometallic.