Rhodium Catalyzed 3-diazochroman-4-one With Unsaturated Carbon-carbon Bond

This thesis consists of three sections.The first section reviews the classical reactions,the application and development of Wolff rearrangement in recent years.The second and third parts discussed the synthesis of 2H-spiro[benzofuran-3,1’-cyclobutan]-2’-one and 2H-spiro[benzofuran-3,1’-cyclobutan]-2’-en-4’-one and its derivatization reation.Both sections are the core of this paper.In the second part,we developed an efficient synthesis of 2H-spiro[benzofuran-3,1’-cyclobutan]-2’-one core skeleton through 3-diazochroman-4-one and alkenes.The synthetic strategy is Rh(II)-catalyzed Wolff rearrangement/[2+2]cycloaddition reaction of 3-diazochroman-4-one and alkenes to obtain 6-Oxa-spiro[3.4]octan-1-one skeleton by one step.Also,the 1,7-dioxaspiro[4.4]nonan-2-one motif,a crucial intermediate in the synthesis of the nature products,was procured through the Baeyer-Villiger oxidation of the 6-Oxa-spiro[3.4]octan-1-one.In the third part,we developed an efficient synthesis of 2H-spiro[benzofuran-3,1’-cyclobutan]-2’-en-4’-one core skeleton through 3-diazochroman-4-one and alkyne.The synthetic strategy is Rh(II)-catalyzed Wolff rearrangement / [2+2]-cycloaddition reaction of 3-diazochroman-4-one and alkynes.2H-spiro[benzofuran-3,1’-cyclobutan]-2’-en-4’-one skeleton was established by one step.Then we focused on the derivatization reaction.A bunche of derivate were obtained,such as β,γ-unsaturated carbonyl compounds through the ring-opening/addition reaction of cyclobutenone and cyclohexene.We also found the aromatization/coupling reaction catalyzed by palladium.Considering its broad substrate scope and good functional group compatibility,this protocol may provide broad applications in organic synthesis.The report about this kind of synthesis methods base on such rigid frames has rarely been reported.