A sub-stoichiometric tungsten-mediated Pauson-Khand reaction : Scope and limitations

Abstract Terminal alkynes do not partake in sequential [2+2+1]/benzoannulation reactions with Fischer carbene complexes and highly reactive and sterically hindered olefins; instead, they undergo a Fischer carbene complex-catalyzed Pauson–Khand reaction (PKR). This result has allowed the development, for the first time, of a tungsten-catalyzed PKR, although of limited scope.