Synthesis of (+)-spirolaxine methyl ether

A short and efficient synthesis of (+)-spirolaxine methyl ether, a metabolite of the fungus Sporotrichum laxum with inhibitory activity against Helicobacter pylori, is described. The synthesis has been carried out by a Prins cyclization, to obtain the [ 6,5]-spiroketal system, and a Wadsworth-Emmons condensation, applied for the installation of the polymethylene chain on the phthalide moiety.