Pure and Applied Chemistry

Abstract: This short review article covers some useful applications of alkynyltungsten compounds to the syntheses of complex lactones. Two types of cyclizations will be emphasized: (1) cycloalkenylation of tungsten-alkynol compounds with aldehydes to give a-alkylidene oxacarbeniums, further leading to a-alkylidene lactones and (2) intramolecular [3+2]-cycloaddition of epoxides to give bicyclic lactones. The new methodologies can provide a short synthesis of enantiopure lactones such as (-) -epilitsenolide C₂, (+) -listenolide C₁, (+) -isodihydromahubanolide A, (+) -blastmycinone, and (-) -epi-blastmycinone.