Synthesis Of 2-sulfonylated And 2-oxyalkylated Pyrrolo[1,2-α] Indole Derivatives With N-propargylindole

Pyrroloindole derivatives,as one of the fused heterocyclic compounds,exist widely in natural products and bioactive molecules.Therefore,the development of environmentally friendly and atom-economical methods for the synthesis of pyrroloindole derivatives has attracted wide attention from chemists.N-propargylindole is a molecule with carbon-carbon triple bond and indole motif.It has multiple reactive sites.As one of the raw materials for the synthesis of pyrroloindole derivatives,it has become an important cyclization precursor.In this thesis,pyrrolo[1,2-a]indole derivatives were synthesized via tandem radical functionalization/cyclization reaction of N-propargylindoles with sodium arylsulfinates or tetrahydrofuran under iodine or visible light photocatalysis.The thesis consists of four chapters.Chapter 1.Progress in Synthesis of Pyrroloindole DerivativesIn this chapter,the recent progress in the synthesis of pyrroloindole derivatives is reviewed in detail from three aspects:metal catalytic synthesis,metal-free catalytic synthesis and visible light photochemical synthesis.Chapter 2.Iodine Promoted Synthesis of 2-Sulfonylated Pyrrolo[1,2-a]indolesIn this chapter,the synthesis of 2-sulfonylated 9H-pyrrolo[1,2-a]indole derivatives by tandem radical sulfonylation/cyclization/isomerization reaction is described,which use sodium arylsulfinates as sulfur-containing building block to react with N-propargylindoles in the presence of I2 under air atmosphere.Get 25 target products with medium to good yield.The protocol has the advantages of readily available starting materials,mild reaction conditions,wide substrate scope and the ability to construct C-C bonds and C-S bonds simultaneously.A possible reaction mechanism is suggested.Chapter 3.Visible Light Photochemical Synthesis of 2-Oxoalkylpyrrolo[1,2-a]-indoles2-Oxoalkyl-9H-pyrrolo[1,2-a]indole derivatives were synthesized by the reaction of N-propargyl indoles and tetrahydrofuran via tandem radical oxoalkylation/cyclization/isomerization reaction under visible light photochemical conditions.The reaction is conducted by using cheap Eosin Y as a photosensitizer and t-butyl hydrogen peroxide as an oxidant under the irradiation of 36 W of fluorescent lamp(CFL).The products are obtained in synthetically useful yield.The method shows simple operation,mild reaction conditions and high atom utility.Chapter 4.Summary and perspectiveIn this thesis focused on theconstruction of a series of pyrrolo[1,2-a]indole derivatives through free radical cyclization/isomerization reactions.In the second chapter,the reaction of N-propargylindoles with sodium arylsulfinate under the promotion of I2 generally gave 2-sulfonylated 9H-pyrrolo[1,2-a]indole derivatives in moderate to good yields.In the third chapter,2-oxoalkyl-9H-pyrrolo[1,2-a]indole derivatives were synthesized by the reaction of N-propargylindoles with tetrahydrofuran under Visible Light Photochemical conditions the yield was only about 38%.The reactivity of N-propargylindoles with tetrahydrofuran was poor,and it was hoped that the yield of this reaction could be improved in future work.so Therefore,we analyzed the reasons for this result through simple theoretical calculation and proposed how to continue to explore in future work.