Recent Advances in Gold catalyzed Tandem Reaction for the synthesis of Heterocyclic Compounds

Gold-catalyzed tandem reactions have been shown to be an all- round synthetic approach to the production of heterocyclic systems, which are of great relevance in the pharmaceutical and materials industries. The purpose is to describe previously unknown over 140 studies regarding the gold-catalyzed tandem reactions and review the progress since the beginning of the decade of 2010th. Main results focus on the formation of biologically active species, for instance, 2-Indenylindole (3-(1H-inden-2-yl)-1H-indoles) with noted activity against different cancer cells; this shows the versatility of the reactions under discussion in medicinal chemistry. This emphasizes that gold (I) catalysts are useful for several transformations such as 1,2-indole migration, C3-propargylation of indoles, synthesis of oxazoles, and fluorinated pyrazoles with moderate to good yields 55– 87%. Dataset at the mechanistic level is remarkably informative towards the catalytic cycle and intermediate species where it has been confirmed that gold(I) catalysis fixes reactive intermediates highly effectively or in other words the species necessary for the bond construct. For example, the 1,2- indole migration that has been prompted by propargylic indoles have been found to furnish intricate indoles that play an essential role in medicinal chemistry. This review is therefore novel in that it provides a state-of-the-art account of gold catalysis with a concern on gold (II) complexes that could lead to new catalytic manifolds and possible improvements in reactivity on tandem methods. Further, it considers the consequences of designing the catalyst and the optimization methods that are used to overcome the problems, for instance, catalyst deactivation and substrate constraint. More potential work should be directed to the improvement of these reactions and the stability of the reaction conditions to broaden the use of gold catalysis in chemical reactions.