Low-valent transition metal induced C-C bond formations: Stoichiometric reactions evolving into catalytic processes

Abstract

A new concept for C-C-bond formations catalyzed by early transition metals in low oxidation state is outlined. It allows to perform intramolecular reductive carbonyl coupling reactions catalytic in titanium, accounts for the first chromium-catalyzed Nozaki-Hiyama-Kishi reactions, and has been successfully applied to titanium-, samarium- or vanadium-catalyzed pinacolization reactions.