High Efficiency Catalysis Of Aryl Alkenyl Nazarov Reaction:Synthesis Of Indanone Compounds

The structure of the indanone compounds has an aryl and five-membered ring structure,which has attracted much attention in recent years because of its existence in a large number of natural products and some drug molecules.There are many methods for synthesizing indanone compounds,and the five-membered ring always the focus of synthesis and the Nazarov reaction is a very important method for constructing five-membered rings.While the method uses the diketene structural compound as the reactant to undergo an intracellular 4? electrification,and the catalyst useually is the Lewis acid and brownsted acid.Since I.N.Nazarov first reported this reaction,it has been widely used to construct five-membered cyclic compounds and developing more types of reaction substrates and catalysts.And the Trauner group has reported the first asymmetric catalysis of this reaction in 2003,Which help the study of the traditional Nazarov reaction more diversified.However,the study of the Nazarov reaction of arylene ketones as diketene analogues is currently developing less and the catalytic structure of the reaction is single,beside the reaction substrate activity is higher.This article has deeply research the problem of the literaturer,use the methyl to replace the 1,3-dicarbonyl structure and with the low active reactants,we have done three works of it.1.The mixing Lewis acid catalytic systemWhen we first design the catalyst we have been inspired by the Pd catalyst,and wetry to design a dual activation mode like the Pd catalyst was.After a series of experiments we found that the combination of Fe(OTf)3 and boric acid can effectively improve the reaction efficiency.And deeply research shows that when the ratio of3,5-tribendymethylbenzeneboronic acid and Fe(OTf)3 is 1: 2.the reaction rate and the reaction time can be the best.Under this condition,a series of substrate extensions were carried out,and many of the substrates which has electron withdrawals get the over 80%yield and better diastereoselectivity.And with the same catalytic mode we successfully synthesis a piece of a natural product.With the analyzingof the product structure we can make sure that the product is thermodynamic control products.Then we presumab the possible reaction mechanism.2.Attempts to study asymmetricWhen we use the Ion change gain the obervisly produce,we try to use the chiral ligands to take place of bipyridine.The salan ligand is a wildly used chiral ligand so we use it attempt to the asymmetric reaction.But when we prepared the ligand,we find that the traditional ligand synthesis route is too complicated,so that we change the traditional route.Finally we get a range of different types of Salen ligands by the new route,which we have been use in the asymmetric attempt of Nazarov reaction through aryl alkenyl ketones.