Denitrogenative C–C and C–X Coupling Reactions of a Carbohydrate Tethered [1,2,3]Triazolo[1,5-a]pyrazine: Access to Chiral 2,5-Disubstituted Pyrazines as Potential Hypoglycemic Agents

A serendipitous base-mediated dehydrotosylation reaction accompanied by a concomitant aromaticity-driven ring opening of a carbohydrate fused 4,5,6,7-tetrahydro-[1,2,3]triazolo[1,5-<i>a</i>]pyrazine has led to the conceptualization of a novel route to the synthesis of chiral 2,5-disubstituted pyrazines that have potential applications as hypoglycemic agents. Denitrogenative ring opening of thus obtained carbohydrate tethered [1,2,3]triazolo[1,5-<i>a</i>]pyrazine in the presence of a variety of aliphatic, aromatic and hetero aromatic boronic acids or BCl₃ delivered the respective chiral 2,5-disubstituted pyrazines efficiently.