“…2,3 Among these, the inverse electron demand Diels-Alder addition (iEDDA, Scheme 1) of 1,2,4,5-tetrazines and olefins, occasionally referred to as CarboniLindsey 4 reaction, has increasingly gained importance in the last few years. Other than iEDDA, 5 SPIEDAC 6,7 (strain-promoted inverse electron demand Diels-Alder cycloaddition), DA inv 8 (Diels-Alder with inverse electron demand) or ihDA/rDA 9 (inverse electron demand hetero Diels-Alder-retro-Diels-Alder) are used as abbreviations. Initially applied for the synthesis of pyridazines, 4,9 iEDDA was introduced as a potential click chemistry scheme almost simultaneously by two groups in 2008.…”