The invention is directed to method for the preparation of pyrrolines of the general formula (I) by catalytic hydration of a nitroketone of the general formula (II) employing a transition metal catalyst and gaseous hydrogen at an elevated pressure in a solvent, optionally in the presence of at least one additive selected among Lewis acids, Brønstedt acids, organic sulfur-containing compounds, organic or inorganic bases, and water scavengers, wherein in formulae (I) and (II) B1, B2, B3, B4, X, R, and T are as defined in the specification, and to a nitroketone of formula (II) to be used as intermediate in the process according to the invention and as pesticidal agent.