Study On Dehydroxylation Of Allyl Alcohols Mediated By Sm(?) Reagent And [3+2] Cycloaddition Aromatization By NHPI-mediated Tandem Electrochemical Oxidation

In the first part of this dissertation,the reductive dehydroxylation/double bond migration reaction of allyl alcohol compounds promoted by allyl bromide in the presence of additives was investigated.Studies have shown that when HMPA was used as the sole additive,the yield of the olefin product formed by dehydroxylation was low.The yield could be improved when H₂O was added as a co-additive.In addition,the use of organic acids as co-additives were screened.It is satisfactory that when methanesulfonic acid?MsOH?was used as a co-additive,the yield was further improved.Thus the allyl alcohols when subjected to the SmI₂/HMPA/MsOH system could afford the alkenes in the yields exceeding 80%.Control experiments showed the SmI₂/HMPA/MsOH system was not effective in dehydroxylation of allyl alcohols to the alkenes.This study has further explored the properties of allyl bromide and broadened the range of applications of allylSmBr in organic synthesis.In the second part,the electrochemical anodizing method was used to realize the tandem oxidation/cyclic/aromatization reaction.In this study,N-substituted tetrahydroisoquinoline and maleimide were selected as the substrates.After screening on the conditions systematically,the efficient tandem oxidation/[3+2]cycloaddition/aromatization reaction was finally achieved by using N-Hydroxyphthalimide?NHPI?as electron transfer promoters,Et₄NBr as electrolytes,MeOH as the solvents and Pt as the electrodes.In this study,the regulation effect of electron transfer promoters on the reaction site was discovered.The above strategy avoids the use of chemical oxidants,light and other harsh conditions.In addition,the reaction bears such advantages as mild conditions,good atomic economy and being environmentally benign,thus providing a green and efficient synthesis of 5,6-dihydropyrrole[2,1-?]isoquinolines.