The regiochemical outcome of a cobalt(ii) catalysed C-H activation reaction of aminoquinoline benzamides with unsymmetrical 1,3-diynes under relatively mild reaction conditions can be steered through the choice of diyne. The choice of diyne provides access to either 3- or 4-hydroxyalkyl isoquinolinones, paving the way for the synthesis of more highly elaborate isoquinolines.

Pyrazole and its derivatives are important azole heteroarenes prevalent in pharmaceutical compounds and have been used as ligands for protein binding, making them valuable targets for synthetic applications. Herein we disclose an electrochemical intermolecular C-H/N-H oxidative annulation of 2-phenylpyrazoles with alkynes using a rhodium(iii) redox regime without any external metal oxidants in a water compatible solvent system. Both symmetrical and unsymmetrical alkynes were shown to be compatible with the optimized conditions.

The formation of C-C/X bonds is essential for the manufacture of a broad range of chemicals and materials used in areas critical for maintaining quality of life in modern society, e.g. pharmaceuticals, agrochemicals and polymers, and for aspects of research in organic chemistry. The use of catalysts for facilitating these reactions is highly desirable due to the improvements in energy and atom economies that can potentially be achieved.The primary objective of the thesis was to explore novel approaches for catalysis of C-C/X bond-forming reactions, both through C-H activation. In paper I, at unable cobalt catalyzed C-H activation-driven annulation of benzamides with unsymmetrical diynes was developed, where either 3- or 4-substitution of the isoquinolone could be steered by the nature of the diyne used. Anunprecedented iridium catalyzed tandem bis-arylsulfenylation of indoles was described (paper II), where an adamantoyl sacrificial directing group plays a key role in the simultaneous direction of arylsulfenylation to the 2- and 4- positions. In paper III, a flow reactor in a lab-on-a-chip device was developed for the Suzuki cross-coupling reaction. Miniaturization provides the opportunity to reduce material consumption. Polyethyleneimine (PEI)-brushes were used for the immobilization of Pd-nanoparticles, and high efficiencies were observed. Collectively, the research underpinning this thesis provides new strategies forC-C and C-X(S) bond formation.

Gold surface-bound hyperbranched polyethyleneimine (PEI) films decorated with palladium nanoparticles have been used as efficient catalysts for a series of Suzuki reactions. This thin film-format demonstrated good catalytic efficiency (TON up to 3.4 x 10(3)) and stability. Incorporation into a quartz crystal microbalance (QCM) instrument illustrated the potential for using this approach in lab-on-a-chip-based synthesis applications.

Described herein is a decarbonylative tandem C-H bis-arylsulfenylation of indole at the C2 and C4 C-H bonds through the use of pentamethylcyclopentadienyl iridium dichloride dimer ([Cp*IrCl2](2)) catalyst and disulfides. A new sacrificial electron-rich adamantoyl-directing group facilitates indole C-H bis-functionalization with a traceless in situ removal. Various differently substituted disulfides can be easily accommodated in this reaction by a coordination to Ir(III) through the formation of six- and five-membered iridacycles at the C2 and C4 positions, respectively. Mechanistic studies show that a C-H activation-induced C-C activation is involved in the catalytic cycle.