Synthesis and properties of new fused bicyclic compounds containing P-B-S linkages

New bicyclic compounds, (P-B)-12-phenyl-12H-dibenzo[d,g][1,3,6,2] dithiapho sphaborocine (3a) and (P-B)-12-cyclohexyl-12H-dibenzo[d,g][1,3,6,2] dithiap hosphaborocine (3b), were synthesized by the reaction of phenyl- and cycloh exylbis(2-mercaptophenyl)phosphine (5a and 5b) with BH3-THF. The structures of 3a and 3b were definitively determined by X-Ray crystallographic analys is. The reaction of tris(2-mercaptophenyl)phosphine (5c) with BH3-THF gave a bicyclic compound, (P-B)-12-{2-[(4-hydroxybutyl)thio]phenyl}-12H-dibenzo[ d,g][1,3,6,2]dithiaphosphaborocine (8).