An Unusual Palladium Complex Involved in an Unusual Rearrangement of Ortho-Palladated Aryldithioacetals

Abstract

The reaction of 1 with Pd(dba)(2), Tl(TfO) and PPh(3) in 1:1:1:2 molar ratios to give 3 implicates (i) an oxidative addition reaction, (ii) a rearrangement involving the cleavage of one HC-S bond and formation of an aryl-S bonds, and (iii) coordination of the Pd(PR(3))(2) group with a ligand intermediate between eta(2)-[ArCH=S((+))To] and kappa(2)-C,S-ArCH((-))STo, which requires the consideration of 3 as intermediate between a Pd(0) and a Pd(II) complex. The coordination of the ligand as a chelating three-membered ring, instead of the expected five-membered ring involving C(10) and S(1), and the partial intramolecular redox process are explained as a consequence of the transphobia of the pair of ligands Ph(3)P/CH(STo)Ar.