Selective Transformations Mediated by Group 4 Metal Cyclopentadienyl Complexes

This chapter provides a brief overview of chemical transformations or syntheses mediated or catalysed by complexes of group 4 elements containing cyclopentadienyl and related ligands. Particular attention has been devoted to selectivity in a broad sense. While the text attempts to take a wider perspective, it focuses on selected recent trends and developments that fall approximately within the last decade (2013–2023). Covered topics comprise new approaches to the synthesis of chiral group 4 metallocenes, radical catalysis with Ti(III) species, photoredox catalysis with group 4 complexes, C–C bond formation and cleavage utilising low valent metallocenes, reactions involving hydro- and carbometallation steps, recent trends in polymerisation catalysis, and several other examples demonstrating the utility of early transition metals in organic synthesis.