LAUSR

Abstract Emerging research in the field of organometallic chemistry is centered on the development of new efficient catalysts for the production of useful organic products via group (nitrene, carbene, oxo) transfer chemistry. Nitrene, carbene and oxo transfer with 3d (base) metals allows for economically viable and sustainable alternatives to generate new C–C, C–X, and X–X (X = N, O) bonds, as compared with precious metal catalysis or lengthy organic synthesis. This review specifically focuses on the evolving group transfer chemistry using mononuclear middle and late transition metal complexes in bulky alkoxide ligand environments. Bulky alkoxides are attractive ligand candidates for this chemistry because their steric and electronic properties generally lead to high-spin electrophilic reactive metal centers. Design and synthesis of well-defined alkoxide complexes are discussed first, with the focus on “non-symmetric” alkoxides [OCR2R′] developed mostly during the last decade. Variation of the size and the electronic nature of substituents in [OCR2R′] allows for the selective formation of bis- or tris(alkoxide) ligand platforms. Next, the reactivity of these complexes in oxo, nitrene, and carbene transfer is described. The electronic structures and reactivity of discrete mononuclear oxo-alkoxide complexes M(OR)n(O) are discussed in the context of bioinorganic (photosystem II) and heterogeneous (zeolites) catalysis. In the chapters describing nitrene and carbene chemistry, the major emphasis is on the electronic structure and reactivity of novel MIII(OR)2(Y ) species (Y = NR, CR2, N3R, N2CR2), which enables a multitude of coupling reactions including catalytic nitrene homocoupling, catalytic coupling of nitrenes and carbenes with isocyanides, as well as rare or unprecedented reductive coupling of azides and diazoalkanes.