Direct cycle between co-product and reactant: an approach to improve the atom economy and its application in the synthesis and protection of primary aminesElectronic supplementary information (ESI) available. See DOI: 10.1039/c6gc01318j

Two important goals of green chemistry are to maximize the efficiency of reactants and to minimize the production of waste. In this study, a novel approach to improve the atom economy of a chemical process was developed by incorporating a direct cycle between a co-product and a reactant of the same reaction. To demonstrate this concept, recoverable 3,4-diphenylmaleic anhydride ( 1 ) was designed and used for the atom-economical synthesis of aliphatic primary amines from aqueous ammonia. In each individual cycle, only ammonia and alkyl halide were consumed, and 1 was recovered in nearly a quantitative yield. In this approach for developing atom-economical protecting agents, 1 showed good performance as a recoverable protecting agent for primary amines. The broad substrate scope, good tolerance to various reaction conditions, and high reaction and recovery rates make 1 a valuable complement to conventional primary amine protecting agents. Recoverable 3,4-diphenylmaleic anhydride for the atom-economical synthesis and protection of primary amines.