Towards to the trans-bromination of 2-styrylpyridine with a palladacycle intermediary and structure analysis for trans-1,2-dibromo-2-styrylpyridine

The simple halogenation of alkynes in conventional organic reactions gives a blend of cis and trans isomers. It is proposed then, a synthesis of stereospecific halogenation of alkynes in trans position, using palladacycle as intermediaries. The recrystallization of the compound obtained by bromination of 2-Styrylpyridine, with cyclepalladium intermediary results in a single crystal, which is subjected to X-ray diffraction. ystal packing is established through weak interactions of three types. The first one is of the type π × π interactions, from symmetry operation, between the centroids. The second one is of the type CX⋯π interactions. And the last type is an anomalous intermolecular interaction between halogens, CX⋯XC, with bond distances smaller than the sum of the van der Waals radii. The conformation on the CC bond is trans and the dihedral angle between the aromatic rings is (with esd approximate) 18.1(3)°.