pp. 1217 - 1226

Abstract

The structures previously assigned to the phenanthrene alkaloids 3-O-demethylthalicthuberine and N-acetyl-seco-N-methyllaurotetanine have been confirmed by total syntheses in which the key step involved formation of ring C of the aporphine alkaloids (±)-isodomesticine and O-benzyl-N-methyllaurotetanine by a radical-initiated cyclization. Opening of ring B of (±)-isodomesticine with methyl chloroformate and subsequent reduction of the N-carbomethoxy group afforded 3-O-demethylthalicthuberine. Similarly, ring-B
opening of N-methyllaurotetanine with acetyl bromide followed by hydrolysis afforded N-acetyl-seco-Nmethyllaurotetanine.