REACTIONS OF SOME SULFUR(II)-CONTAINING AND IODINE(III)-CONTAINING ELECTROPHILES WITH O-TRICYCLO[6.2.1.0(2,7)]UNDECA-4,9-DIENE-3,6-DIONE

Reaction of ArSCI (Ar = phenyl or ortho-nitrophenyl) -tricyclo[6.2.1.0 (2,7)]-undeca-4,9-diene-3,6-dione (1) results in anti addition across the norbornene carbon-carbon double bond with concomitant aromatizatio n of the cyclohexenedione ring, thereby affording 4 (87%) and 5 (63%), respectively. The corresponding reaction of PhSCI with 1 in the prese nce of added Ag(I) proceeds via polar addition across the norbornene c arbon-carbon double bond with concomitant intramolecular nucleophilic trapping of an intermediate episulfonium ion by a distant C=O group, t hereby affording 6 (57% yield). The reaction of PhICI(2) with 1, when carried out in the presence of SbCI5 or AgBF4, proceeds with concomita nt Wagner-Meerwein rearrangement and aromatization to afford adducts 7 a and 8, respectively.