Application Of Triazole-nhc In Annulation Reaction And Study On Chiral Triazole-catalyzed Asymmetric Reaction Of Isatin And Indole

The quest for the discovery of efficient,ecofriendly catalysts for the construction of carbon–carbon bonds is a perennial issue in organic synthesis.The number of related publications on NHCs and their metal complexes has continuously increased in the past two decades.The general aspects of the synthesis and catalytic potential of N-Heterocyclic carbenes and their coordination chemistry have been presented in a good few review papers and books.However,the application of 1,2,3-triazole compounds are a great deal less than 1,2,4-triazole compounds as triazole-NHCs.In this paper,we investigated a 1,2,3-triazole-NHC and received favorable results in annulation reaction;On the other hand,1,2,3-triaozle as a excellent ligand which have a specific five membered nitrogenous heterocyclic structure.However,it is rarely reported in asymmetric catalysis.In this work,we combined L-proline with 1,2,3-triazole compounds,synthesized a sequence of chiral L-proline-1,2,3-triazole ligands,which will be applied to catalyze asymmetric reaction.Innovative achievements are acquired as follows:With 2-Iodobenzylalcohol and benzyl bromide as raw,we synthesized a 1,2,3-triazole-NHC after five-step reaction.And then NHC was applied to catalyze annulation reaction of enals with vinyl ketones to form [2H]-pyranones,which achieved great results in optimum conditions and expanded the application prospect in 1,2,3-triazole-NHC.With benzyl bromide and sodium azide as raw,we synthesized a series of chiral L-proline-1,2,3-triazole ligands after six-step reaction.A variety of strategies and experimental methods are adopted to obtain the final products,which will be applied to catalyze asymmetric reaction of isatin and indole.In a series of experiments,the relative superiority and application prospect of this kind of ligand are exhibited,which lays a foundation for further exploration and application of the catalyst.