Electronic and steric effects induced by various phosphine ligands on the regioselective rhodium-catalysed hydroformylation of butyl acrylate and enamides were investigated in this thesis. The first chapter describes the hydroformylation reactions reported in the literature, followed by chapter two, which presents the synthesis of modified dppb and phosphite ligands based on a biphenol and binol backbone. Ligand design represents a straightforward way to control the outcome of f the reaction, such as the catalytic regioselectivity and activity. The influence of modified dppb and phosphite ligands as well as some other parameters on the hydroformylation reaction was investigated; this forms the content of the third chapter contained within this thesis. As a result of the work featured here, we deduced that because electron deficient phosphine and phosphite ligands showed an increase in the rate of the reaction for butyl acrylate, leading to a higher activity of the rhodium catalyst, it appears that the CO dissociation is the rate-determining step; this is in line with the literature. The maximum rate and branched selectivity (95%) was obtained with dppbCF3 (TOF = 4743 hoI). This result was further extended to enamides in Chapter 4, where a similar observation on the reactivity was observed when using phosphite ligands bearing electron-withdrawing substituents. One of the most significant results is seen in the application of phosphite ligands for rhodiumcatalysed hydroformylation of enamines, which is to our knowledge, have not been previously employed for this type of the reaction. High-branched selectivity (up 99%) and high rate were observed in the hydroformylation ofvinylphthalimide in the presence of bulky phosphites, where the reaction was complete in less than 1 h.