First cross-coupling reactions on tetrazines.

[reaction: see text] A series of substituted chlorotetrazines were reacted with different terminal alkynes under Sonogashira or Negishi coupling conditions to furnish alkynyl-tetrazines in good to moderate yield. The electron-donating properties of the substituent on the tetrazine core were found to have a significant influence on the success of the reaction. These results constitute the first cross-coupling reactions on tetrazines.