Synthesis and Reactivity of 5-Bromopenta-2,4-diynenitrile (BrC 5 N) an Access to π-Conjugated Scaffolds

N. Kerisit (1) , R. Ligny (1) , E.S. Gauthier (1) , J.-P. Guegan (1) , Loic Toupet (2) , J.-C. Guillemin (1) , Y. Trolez (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 IPR - Institut de Physique de Rennes

The synthesis of 5-bromopenta-2,4-diynenitrile (BrC 5 N) in three steps from commercially available compounds is reported. Reacting 5-bromopenta-2,4-diynenitrile with secondary amines led to the formation of stable butadiynamines or enynenitriles, depending on the nature of the amine reactant. The reaction of 5-bromopenta-2,4-diynenitrile with simple terminal alkynes in the presence of secondary amines, copper, and palladium catalysts, provided a straightforward access to original polyfunctional carbon-rich scaffolds. In this work, different alkynes and secondary amines were tested, which allowed for the preparation of a family of substituted dienes. Given the high synthetic potential of 5-bromopenta-2,4-diynenitrile, we also prepared iodinated counterparts of this compound, that is, 5-iodopenta-2,4-diynenitrile and its lower homologue 3-iodopropiolonitrile. The UV-visible spectrum of some relevant compounds was also recorded.

Keywords: dienes; alkynes; enynes; ynamines

Domains: Chemical Sciences; Organic chemistry; Chemical Sciences; Catalysis

N. Kerisit, R. Ligny, E.S. Gauthier, J.-P. Guegan, Loic Toupet, et al.. Synthesis and Reactivity of 5-Bromopenta-2,4-diynenitrile (BrC 5 N) an Access to π-Conjugated Scaffolds. Helvetica Chimica Acta, 2019, 102 (3), pp.e1800232. ⟨10.1002/hlca.201800232⟩. ⟨hal-02089223⟩