Palladium-Catalyzed C-N Coupling in the Synthesis of Benzodiazepines

This review article is focused on the reactions, which include the syntheses of various classes of benzodiazepines in the presence of a Pd catalyst. The catalyst used here belongs to the transition metal group and nowadays, there is keen interest in numerous methods for the coupling reaction in the presence of a catalyst to prepare the biologically active heterocyclic compounds. In particular, the use of domino reactions as inter- or intramolecular processes is reported as an efficient and eco-compatible tool to obtain differently functionalized benzodiazepines. 2,3-benzodiazepines having pharmaceutical interest are synthesized via asymmetric catalysis. The catalyst used in this synthesis is palladium-chiral bidentate phosphine complex and thiazolium-derived carbine. The 1,3-benzodiazepines are prepared by A³ coupling. In this reaction, the propargylamine was first added to the isocyanates. After that, hydroxylation of alkyne occurs in the presence of a Pd catalyst in a one-pot manner to yield the 1,3-benzodiazepines.