Understanding the speciation of homogeneous catalysts in solution under turnover conditions and their dynamic evolution over the course of the reaction presents a long-standing challenge for traditional mechanistic investigations based on initial rate analysis and stoichiometric test experiments. This thesis shows how high resolution FlowNMR spectroscopy is a powerful non-invasive tool for studying air-sensitive transition metal catalysis under working conditions in real time, as exemplified by the investigation of the photochemical oxidation of N-allybenzylamine requiring a sustained input of light and air, and the asymmetric transfer hydrogenation of aryl ketones from isopropanol using Noyori catalysts.