Tungsten(0) <i>η</i><i>²</i>-Thiophene Complexes: Dearomatization of Thiophene and Its Facile Oxidation, Protonation, and Hydrogenation

Abstract

Complexes of the form TpW(NO)(PMe3)(η2-thiophene) have been synthesized in 31−40% yield by reduction of TpW(NO)(PMe3)(Br) in the presence of the thiophene ligand. The dynamics of protonation and the subsequent deprotonation for the corresponding 2H-thiophenium complexes have been investigated. Hydrogenation of the uncoordinated double bond was accomplished, and sulfur−carbon, sulfur−oxygen, and carbon−carbon bond-forming reactions were explored with these complexes.