Regioselective Synthesis of Isoquino[1,2-b][3]benzazepines (Homoprotoberberines) through 11-Membered-Ring Stilbene Lactams Obtained by Radical Macrocyclization.
Silylated 11-membered-ring stilbene lactams 3 (E and Z) were easily prepared by intramolecular addition of an aryl radical to a trimethylsilylacetylene. Oxidation of their hindered stilbene double bonds with dioxiranes gave oxidative cleavage of their electron-rich aromatic rings. However, reduction of the amide to an amine functionality in both lactams (E and Z) triggers a regioselective [7,6]-transannular cyclization to isoquino[1,2-b][3]benzazepines (homoprotoberberines).
Rodríguez
Gema
G
Institute of Organic Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Castedo
Luis
L
Domínguez
Domingo
D
Saá
Carlos
C
Adam
Waldemar
W