Synthesis of 2,6-diaryl-4,8-dihydroxy-3,7-dioxabicyclo[3.3.0]octanes

Abstract

A series of 2,6-diaryl-4,8-dihydroxy-3,7-dioxabicyclo[3.3.0]octanes, including 4,8-dihydroxysesamin, a naturally occurring lignan, have been prepared via the corresponding dilactones. The ¹H and ¹³C n.m.r. spectra have been compared and the bistoluene-p-sulphonate of 4,8-dihydroxyeudesmin has been reduced by lithium aluminium hydride to give (±)-eudesmin. Since this synthesis does not involve ring-opened intermediates and starts from a dilactone of established structure, it represents the first unequivocal synthesis of such a lignan.