A revised structure for neogmelinol: determinations of configurations in tetrahydrofuranoid lignans

Abstract

Neogmelinol is shown to be a stereoisomer rather than a structural isomer of gmelinol and isogmelinol, and its absolute configuration is established. A general criterion is established for assignment of stereochemistry in lignans of the 3,7-dioxabicyclo[3,3,0]octane series by the use of n.m.r. spectra. The relative stabilities of the isomers are discussed. The configuration of sesangolin is assigned.