The First Phosphine-Catalyzed Insertion of Tellurium into Sn−Sn and Pb−Pb Bonds:  A Simple and Efficient Route to R3MTeMR3 (M = Sn, Pb)

In the presence of a catalytic amount of a phosphine, elemental tellurium efficiently inserts into Sn−Sn and Pb−Pb bonds under mild conditions to give the corresponding tellurides R 3 MTeMR 3 (M = Sn, Pb) in quantitative yield. Mechanistic study shows that first a phosphine telluride R‘ 3 P Te is formed via the reaction of R‘ 3 P with tellurium, which subsequently reacts with (R 3 M) 2 to produce (R 3 M) 2 Te and concomitantly regenerates R‘ 3 P to restart another cycle of the catalytic insertion.