Both (+)- and (-)-umbelactone have been synthetized from (R)-γ-hydroxymethyl-γ-butyrolactone and D-ribonolactone, respectively. The absolute configuration of the natural product has shown to beR-(+).
An efficient and convenient strategy for the enantioselective synthesis of enantiomerically enriched umbelactones is described utilizing a lipase-mediated resolution protocol, Baylis–Hillman reaction and ring closing metathesis as key steps. The lipase-resolution is carried out using several lipases from various sources in different solvents to afford the required intermediate 8 in good yield and high