Microwave-Assisted Cu(I)-Catalyzed Synthesis of Unsymmetrical 1,4-Diamino-2-butynes via Cross-A³-Coupling/Decarboxylative A³-Coupling

1,4-Diamino-2-butynes display both chemical and physiological properties. Here a highly efficient synthesis avenue to generate unsymmetric 1,4-diamino-2-butynes has been developed by microwave-assisted Cu(I)-catalyzed cross-A3-coupling/decarboxylative coupling of two different amines, formaldehyde, and propiolic acid through a domino process. This multicomponent reaction provides a series of target products in moderate to good yields with high chemoselectivity.