Multiple pathways in Cp2TiCl2 - catalyzed reaction of tetraalkyl-substituted pyrazines with EtAlCl2 and Mg.

There exist a number of classical methods for the synthesis of substituted pyrazines. Among this variety of reactions, the synthesis of substituted pyrazines from nitriles stands out neither in the number of known examples nor in product yields. However, the one-stage character of the transformation, together with the uncertainty of its mechanism, aroused our interest in this catalytic reaction. Here we report the successful implementation of Cp2TiCl2 -catalyzed reaction of aliphatic nitriles with EtAlCl2 and Mg, which led to the selective preparation of 2,3,5,6-tetraalkyl-substituted pyrazines, 2,4,5-trisubstituted-1H-imidazole or 2-aminocyclopent-1-ene-carbonitrile depending on reaction conditions and substituents.