Selective Schmidt-Aubé Reaction And Olefin Functionalization Of Allyl Azide Mixtures

Allyl azides are a unique class of azides that can rearrange to form a mixture of isomers,including cis-trans double bond isomers with azide at the end and the middle azide isomers with terminal olefins.Taking advantage of the reactivity difference among three isomers,one of the isomers is reacted(azide or olefine)through selective reaction conditions,while the other isomers do not participate in the reaction or the reaction rate is very slow,so that the isomers that do not participate in the reaction can be converted into isomers that can participate in the reaction by rearrangement,resulting in the formation of a single product,and thus this greatly increase the applications of allylic azides in the organic synthesis.This thesis is mainly divided into three parts:1.Synthesis of allyl azide mixtures.In this chapter,by comparing the three synthesis methods,the optimal synthesis method was found out,and the synthesis of three types of allyl azide mixtures of straight chain,branched chain and hydroxyl substitution was completed.The first method is that allyllic halide is prepared by olefin metathesis reaction between terminal olefin and allyl bromide,and then replaced by sodium azide to generate allyl azide mixture.The second method is that the terminal olefin undergoes an olefin metathesis reaction with allylic acetate,and a hydrolysis reaction to prepare an allyl alcohol compound,and is then substituted by DPPA to generate an allyl azide mixture.The third method is to prepare allyllic alcohol compounds through Grignard reaction of aldehyde,and then to prepare allyl azide mixture by DPPA substitution.Method 3 is the optimal synthetic method,and the synthesis and analysis of straight-chain,branched-chain and hydroxyl-substituted allyl azide mixtures are completed.2.Selective Schmidt-Aubé reaction of substituted allyl azide mixtures.Based on 4 substituted allyl azide mixtures,screened are the Schmidt-Aubé reaction acid catalyst and the amount of azide,solvent,temperature and other factors,and finally determined the optimal reaction conditions:at room temperature,boron trifluoride ether(3.0 equiv),hydroxyallyl azide mixture(3.0 equiv),hexafluoroisopropanol as the reaction solvent and the reaction concentration was 0.5M,to afford the best yield.Subsequently,we carried out substrate expansion,reaction intermediate separation,reaction mechanism analysis and reaction stereoselectivity studies,and a total of 33 products were synthesized.3.Study on olefin functionalization of allyl azide mixtures.The asymmetric hydroboration and radical fluorophosphating reactions of allyl azide mixtures are explored.In the aspect of asymmetric hydroboration reaction,the catalyst,reaction temperature,solvent and reaction feed amount were screened,and a product with an enantiomeric excess of 64%was obtained.However,many side reactions resulted in a low yield.In the aspect of free radical fluorine phosphating reaction,after screening the catalyst and dosage,solvent,feeding ratio and other factors,we determined the conditions and obtained the fluorine phosphating product of allyl azide mixture.However,the reaction yield is low and needs further exploration.