Stereoselective methoxylation at the 11β-position of the erythrinan skeleton: total synthesis of (±)-erythristemine
Abstract
Treatment of cis-erythrinan-8-one or 1,7-cyclo-cis :erythrinan-8-one with ceric ammonium nitrate in methanol gave the appreciable yields of the corresponding 11β-methoxy compounds; these were converted into the natural 11-oxygenated erythrinan alkaloid, erythristemine, in high yield.