Metal-hydride-catalyzed transformations have become an efficient and widely explored way of constructing C(sp3)-C(sp3) carbon bonds. Unlike the more traditional cross-couplings, which often require preformed organometallic reagents, these reactions employ readily available olefins as pronucleophilic reaction partners and generate the active nucleophilic species in situ. As a result, they typically offer broad substrate scope and good functional group tolerance. In this thesis, metal-hydride catalysis--specifically copper- and nickel-based systems--is investigated for its application in the valorization of lignin-derived phenolics and in the enantio- and diastereoselective hydroalkylation of alkenes.

In the context of biomass valorization, considerable effort has been dedicated to developing selective and high-yielding methods for lignin depolymerization. On the other hand, synthetic methodology applicable to the subsequent chemical elaboration of the obtained monomers remains comparatively underdeveloped. In the first study presented in this thesis, we describe two copper-catalyzed reactions for the installation of allyl and alkynyl groups at the benzylic position of lignin-derived phenolics. These transformations are part of two-step synthetic sequences that begin with the conversion of phenolics into benzyl hexafluoroisopropyl ethers. Upon their activation in the subsequent reaction, these afford the reactive para-quinone methide intermediates, which react with organocopper nucleophiles generated either via allene hydrocupration or alkyne deprotonation.

The latter chapters of this thesis present our work on nickel-hydride catalysis for the asymmetric construction of carbon-carbon bonds. In the first project, we developed a cross-coupling-type reaction between (Z)-fluoroalkenes and (a)cyclic alpha-haloamides to access a diverse array of fluorinated compounds bearing two adjacent stereogenic centers. The protocol displayed high levels of both enantio- and diastereoselectivity, along with excellent functional group compatibility. In the subsequent study, we developed a nickel-catalyzed dynamic kinetic asymmetric hydroalkylation of unsaturated cyclic phosphinates. In this transformation, the two enantiomers of the starting alkene were interconverted by nickel-catalyzed double-bond migration. As they then engaged in the cross-coupling step with different reaction rates, a single product regio- and stereoisomer could be formed with high reaction selectivity.