Synthesis of Symmetrical 1,3-Diynes via Cross-Coupling Reaction of Alkynyl Bromide with Alkynyl Aluminum Catalyzed by Nickel

1,3-Diyne compounds are important inter mediates in organic synthesis, which are widely used in pharmaceutical chemistry, organic synthesis and materials science. A highly efficient for the synthesis of 1,3-diyne via cross-coupling of alkynyl bromides with alkynyl aluminium reagents catalyzed by nickel has been developed. The coupling reaction of alkynyl bromides with alkynyl aluminium reagents mediated by Ni(acac)(2) (5 mol%)/l,2-bis(diphenylphosphino)ethane mckel(II) chloride (DPPE) (10 mol%)in 1,2-dimethoxyethane afforded the corresponding coupling products 1,3-diyne in good to excellent yields(up to 90%) at room temperature for 5 h. The coupling reaction of alkynyl aluminum with different substituents and alkynyl bromine with vanous substituents can afforded the coupling products in good yields. Importantly, the alpha-ethynylnaphthalene and 2-ethynylthiophene were also suitable for the reaction. This process is simple and easily performed, which provides an efficient method for the synthesis of 1,3-diynes derivatives.