Formation of New 5,11b-Bridged Isoindolo[2,1-b]isoquinolinones Alkaloids through a Tandem Pummerer/π-Cationic Cyclization

[formula: see text] The tandem Pummerer/pi-aromatic cyclization of alpha-acyliminium ion, leading efficiently in "one pot" to thiopoxyareno-bridged isoindoloisoquinolinone incorporating the arylthio group, has been demonstrated for the first time. During this sequence the angular hydroxylated isoindoloisoquinolinone, resulting from the Pummerer-type cyclization, was also obtained.