Synthesis of functionalized unsymmetrical 1,3-butadiene-3-yne derivatives from β-halo styrene derivatives and their application in the synthesis of trisubstituted pyridines

An approach for the synthesis of functionalized unsymmetrical 1,3-butadiene-3-yne derivatives is reported starting from β-halo styrene and phenyl acetylene derivatives in the presence of PdCl₂ and CuI catalysts. Functional groups such as aldehyde, cyano and ester groups are well tolerated and afford the desired functionalized dienynes. Further, these 1,3-buta-diene-3-yne derivatives are utilized for the synthesis of novel trisubstituted pyridine derivatives.