Ml. Spera et Wd. Harman, Electrophilic additions to eta(2)-thiophene complexes: Synthesis of novel thiophenium and thiafulvenium species, ORGANOMETAL, 18(16), 1999, pp. 2988-2998
A series of complexes of the form [Os(NH3)(5)(eta(2)-L)](OTf)(2) (where L =
thiophene and OTf = trifluoromethanesulfonate, i.e., triflate) are synthes
ized and characterized and their reactivities with electrophilic reagents a
re examined. Depending on the electrophile and the substitution pattern of
the coordinated thiophene, direct electrophilic addition occurs at either t
he sulfur, C2, or C3, affording thiophenium complexes. Some elementary tran
sformations of selected thiophene complexes are exploited to prepare novel
1- and 2-thiafulvenium salts.