54 Diazines
Negishi cross-couplings with organozinc reagents and Stille reactions with stannanes, prepared by various means, have
been utilised in the diazine series.
Pericyclic reactions
All the diazines, providing they also have electron-withdrawing substituents, undergo Inverse Electron Demand
Diels–Alder (IEDDA) additions with dienophiles, the ‘inverse-electron-demand’ relating to the fact that in ‘normal’
Diels–Alder reactions the diene component is electron-rich. Intramolecular reactions occur the most readily, and even
in the absence of activating substituents. The immediate products of such processes usually lose nitrogen (pyridazine
adducts) or hydrogen cyanide (adducts from pyrimidines and pyrazines) to generate benzene and pyridine products,
indeed this can be viewed as a means for the ring synthesis of pyridines.