Organoboron compounds have been widely used in carbon-carbon bond formation reactions in organic synthesis and catalysis. This thesis is focused on cross-coupling reactions of allyl-, allenylboronic acids and their ester derivatives via transition metal catalysis or transition-metal-free processes.

The first part of the thesis describes Cu-catalyzed C(sp³)-C(sp³) formation reactions involving allylboronic acids and α-diazoketones. This coupling process shows high γ-regioselectivity, resulting in branched allylic products. When stereodefined cyclic allylboronic acids were employed as the substrate, the relative facial configuration was retained in the reaction product.

The second part involves Pd-catalyzed cross-coupling of allylboronic acid and α-diazoketones. The reaction proceeds with high α-regioselectivity, affording linear allylic products. Accordingly, the palladium- and copper-catalyzed cross-coupling of allylboronic acid and α-diazoketones occurs with opposite regioselectivity.

The third part concerns a new transition-metal-free carbon-carbon bond formation between allenylboronic acids and in situ generated diazo compounds. The diazo compounds are generated from tosylhydrazones in the presence of base. The reaction is suitable for synthesis of densely substituted conjugated dienes with high Z-selectivity.

In the final part, the allylation of quinones with allylboronates is presented. The reaction was performed without any catalyst or additive. Various quinones can be employed as substrates, including unsubstituted, monosubstituted benzoquinones and naphthoquinones.

Tosylhydrazones and allenylboronic acids underwent a transition-metal-free reductive coupling reaction. This process is suitable for synthesis of tetra- and pentasubstituted conjugated dienes. The corresponding allenyl-Bpin substrate showed a very poor reactivity. The reaction is suggested to involve coupling of the in situ formed diazo compound and allenylboronic acid. The intermediate formed in this coupling undergoes allenyl migration followed by protodeboronation to furnish a conjugated diene as major product.

In this study; we present the synthesis of new, Stereodefined allylboronic adds employed to investigate the stereochemistry of the Cu-catalyzed cross-coupling of allylboronic acids with alpha-diazoketones. According to our results, this reaction proceeds with retention of the relative configurtion of the allylberonic acid substrate. We suggest that the stereoinduction step involves a syn S(E)2'-type transrnetalation of the allylboronic acid substrate with a Cu-carbene species.

Palladium catalyzed cross-coupling of allylboronic acids with a-diazoketones was studied. The reaction selectively affords the linear allylic product. The reaction proceeds with formation of a new C(sp(3))-C(sp(3)) bond. The reaction was performed without an external oxidant, likely without the Pd-catalyst undergoing redox reactions.

Copper-catalyzed cross-coupling of substituted allylboronic acids with alpha-diazoketones was studied. This allylation reaction is highly regioselective, providing the branched allylic product. The process involves creation of a new C(sp(3))-C(sp(3)) bond by retaining the keto functional group of the alpha-diazoketone precursor.

Allylboronates undergo C-H allylation of unsubstituted or monosubstituted benzoquinone and naphthoquinone substrates. In the case of 2,5- or 2,6-disubstituted quinones addition involving the substituted carbon takes place. Allylation with stereodefined allylboronates occurs with retention of the configuration.

We demonstrate how the acquisition and processing of 3D electron diffraction data can be extended to characterize structural features on the mesoscale, and show how lattice distortions in superlattices of self-assembled spherical Pd nanoparticles can be quantified by three-dimensional small-angle electron diffraction tomography (3D SA-EDT). Transmission electron microscopy real space imaging and 3D SA-EDT reveal a high density of stacking faults that was related to a competition between fcc and hcp arrangements during assembly. Information on the orientation of the stacking faults was used to make analogies between planar defects in the superlattices and Shockley partial dislocations in metallic systems.