INSERTION OF IRIDIUM INTO C-H AND C-S BONDS OF 2,5-DIMETHYLTHIOPHENE,2-METHYLBENZOTHIOPHENE AND 4,6-DIMETHYLDIBENZOTHIOPHENE

C-H insertion thienyl products are selectively formed at early times o f the interaction of the unsaturated 16e(-) fragment [(triphos)IrH] wi th 2,5-dimethylthiophene (Me2T), 2-methylbenzothiophene (MeBT) and 4,6 -dimethyldibenzothiophene (Me2DBT) [triphos = MeC(CH2PPh2)(3)]. C-S in sertion to give six-membered metallathiacycle products occurs as a the rmal step only for Me2T and MeBT. The C-S insertion products are isola ted as both kinetic and thermodynamic stereoisomers. The thermodynamic C-S insertion product of MeBT, endo-[(triphos)Ir(eta(3)-S,C,C-S(C6H4) CH=C(Me)H)], has been characterized by X-ray diffraction studies. (C) 1997 Elsevier Science S.A.