YbCl3-catalyzed one-pot synthesis of dihydropyrazines, piperazines, and pyrazines

A simple and efficient synthetic approach to dihydropyrazines via YbCl3-catalyzed reaction of α-hydroxyketones with diamines under mild conditions was developed. The corresponding 2,3-subsitituted piperazines and pyrazines were obtained through tandem conversion of dihydropyrazines with good yields.