M. Curini et al., A facile and convenient synthesis of 1,2,3,6-tetrahydropyridazines using azodicarboxylates under lanthanum triflate catalysis, HETEROCYCLE, 55(8), 2001, pp. 1599-1604
The hetero-Diels-Alder reaction catalyzed by lanthanum triflate hydrate usi
ng diethyl azodicarboxylate as dienophile, yielding differently substituted
1,2,3,6-tetrahydropyridazines, is described.