Hydroaminomethylation of the Renewable Limonene with Ammonia in an Aqueous Biphasic Solvent System

With the hydroaminomethylation of the natural compound limonene with ammonia an atom‐economic method for the synthesis of primary amines is described. This tandem reaction allows the direct conversion of the unfunctionalized monoterpene to a valuable amine product. For the first time, ammonia served as substrate to result in a maximum primary amine yield of 25 %. To overcome unwanted side reactions, a biphasic solvent system was used, consisting of an aqueous catalyst phase and an organic product phase. As catalyst the water‐soluble transition metal complex Rh(cod)Cl]₂/triphenylphosphine trisulfonate was chosen. In combination with the surfactant hexadecyltrimethylammonium chloride it provided a good phase interaction and the possibility for easy phase separation after the reaction.