Studies toward a synthesis of trilobatin B,a lignan from the liverwort Bazzania trilobata:asymmetric construction of the tetrahydrofuran segment

摘要

A novel and sereocontrolled process is described for the asymmetric synthesis of the tetrahydrofuran segment of a 2,3-dicarboxy-6,7-dihydroxy-1-(3',4'-dihydroxyphenyl)-1,2-dihydronaphthalene mono-ester,trilobatin B,a lignan from the liverwort Bazzania trilobata.Thekey cis-substituted lactone ring was constructed in a stereoselective manner by Horner-Emmons reacton followed by the subsequen ttandem Michael addition and cyclization of two types of lactol intermediates elaborated from natural sources.