Low-valent early transition metals are often intrinsically highly reactive as a result of their strong propensity toward oxidation to more stable high-valent states. Harnessing these highly reducing complexes for productive reactivity is potentially powerful for C–C bond construction, organic reductions, small-molecule activation and many other reactions that offer orthogonal chemoselectivity and/or regioselectivity patterns to processes promoted by late transition metals. Recent years have seen many exciting new applications of low-valent metals through building new catalytic and/or multicomponent reaction manifolds out of classical reactivity patterns. In this Review, we survey new methods that employ early transition metals and invoke low-valent precursors or intermediates in order to identify common themes and strategies in synthesis and catalysis.
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321. Tomson, N. C., Arnold, J. & Bergman, R. G. Halo, alkyl, aryl, and bis(imido) complexes of niobium supported by the β-diketiminato ligand. Organometallics 29, 2926–2942 (2010).
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