Regio- and chemoselective multiple functionalization of chloropyrazine derivatives. Application to the synthesis of coelenterazine.

Successive regio- and chemoselective metalations of chloropyrazines using TMPMgCl x LiCl and TMPZnCl x LiCl furnish, after trapping with electrophiles, highly functionalized pyrazines in high yields. Application to a synthesis of coelenterazine, a bioluminescent natural product in jellyfish Aequorea victoria, in nine steps (9% overall yield) is reported.