Redox chemistry of discrete low-valent titanium complexes and low-valent titanium synthons

Titanium is a versatile metal that has important applications in practical synthesis, though this is typically limited to stoichiometric reactions or Lewis acid catalysis. Recently, interest has grown in using titanium and other early-metals for redox catalysis; however, notable limitations exist due to the thermodynamic preference of these metals to adopt high oxidation states. Nonetheless, discrete low-valent titanium (LVT) complexes and their synthons (titanium complexes which chemically behave as LVT sources) are known. Here, we detail the various ligand platforms that are capable of stabilizing LVT compounds and present the redox chemistry of these systems. This includes a discussion of recent developments in the use of LVT synthons for accessing fully reversible oxidative-addition/reductive-elimination reactions.

Automated summary

Titanium is a versatile metal with important applications in practical synthesis, typically limited to stoichiometric reactions or Lewis acid catalysis. Interest has grown in using titanium and other early-metals for redox catalysis, but limitations exist due to their thermodynamic preference for high oxidation states. However, low-valent titanium complexes and their synthons are known, and recent developments have focused on reversible oxidative-addition/reductive-elimination reactions using these systems.