Dioxirane epoxidation of 10-membered-ring stilbene lactams as synthetic precursors to protoberberines

Article abstract of DOI:10.1021/jo981829n

Silylated stilbene lactams 1, prepared by intramolecular addition of an aryl radical to a trimethylsilylacetylene, were converted into protoberberines by dimethyldioxirane (DMD) epoxidation and subsequent acid- catalyzed cyclization of the epoxysilane with HCl. Treatment of the nonsilylated trans- and cis-stilbene derivatives with DMD afforded 13- hydroxytetrahydroprotoberberines and 13a-hydroxy-13- ketotetrahydroprotoberberines as the main products. Tetrahydroprotoberberines were also obtained in excellent yields by the reaction of both silylated and nonsilylated lactams with hydriodic acid.