MIA Directed Acetoxylation Of ?-C-H Bonds

The carbon-hydrogen bond activation reaction has shown great advantages compared with the traditional synthesis methods.It has gradually become one of the main means of organic chemical synthesis reaction in recent decades,the transition metal has played an important role in carbon-hydrogen bonds activation,especially the palladium has been extensively studied due to its excellent properties.In the palladium-catalyzed carbon-hydrogen bond activation reaction,various kinds of directing groups have been gradually developed and applied to practical synthesis of natural products and drug molecules.In recent years,the endless stream of carbon-hydrogen bond activation methods have been greatly developed and progressed.However,in the case of a directed activation reaction,the directing group is disassembled or converted into more valuable fragments after synthesis of the target product,there are still remain technical difficulties,and it was an insurmountable obstacle on the road of organic synthesis.The search for a group that is easy to be removed or easy to transform in situ is obviously an urgent problem to be solved.In the field of carbon-hydrogen bond activation,alkylation,alkoxylation,acetoxylation and hydroxylation are frequently used by chemists,and acetoxylation is the most widely studied due to its applicability.The development of carbon-hydrogen bond-activated acetoxylation reaction was discussed.Some classic synthesis cases were briefly analyzed,and our methods were improved for the shortcomings of previous work.Finally,a high efficiency was obtained.A method for synthesizing?-acetoxylated products,which has high reactivity and chemical selectivity,fully demonstrates the unique advantages of this method in synthesis,and provides a new method for selective acetoxylation modification.In the course of our experiments,a large number of substrates were investigated in an universal manner.Based on the template reaction substrate,the side chains of various alkylamines were replaced and the acetoxylation reaction was carried out.The results showed that most of the substrates were good,target prouducts can be obtained in the reaction,which is very valuable for the activation of inert?-C(sp~3)-H,indicating that the method adopted in this subject,and has good economic value and application value.At the same time,we also carried out a universal investigation of the benzylamine substrate,observed the effect of different substituents on the reaction at different sites of the benzene ring.The experimental results showed some tolerance to the effects of steric hindrance and electrical factors in these reactions,and the target compounds were obtained in acceptable yield.Finally,we proposed feasible ideas and schemes for the subsequent conversion of the obtained acetoxylated products.Using the special structure of the MIA-directing group and the characteristics of the acetoxy group itself,it is very possible to undergo a series of functional group transformations.And once this method is realized,the?-hydroxydipeptide derivative will be obtained,meanwhile,it will bring higher practical application value,and also have important significance and value in the selective modification of subsequent complex natural products and the synthesis of biologically active dipeptide compounds.