title: Dioxirane Epoxidation of 10-Membered-Ring Stilbene Lactams as Synthetic Precursors to Protoberberines.
abstract: 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.
authors.affiliation: Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Gema
authors.initials: G
authors.lastname: Rodríguez
authors.forename: Luis
authors.initials: L
authors.lastname: Castedo
authors.forename: Domingo
authors.initials: D
authors.lastname: Domínguez
authors.forename: Carlos
authors.initials: C
authors.lastname: Saá
authors.forename: Waldemar
authors.initials: W
authors.lastname: Adam
authors.forename: Chantu R.
authors.initials: CR
authors.lastname: Saha-Möller