| Addition of sulfonyl radicals to alkenes and alkynes provides a highly effective means for the preparation of sulfones.Sulfonyl radicals can be efficiently generated from readily available precursors via single electron oxidation or single electron reduction under visible-light photocatalysis,and thus a variety of functionalized sulfones can be prepared by using this strategy.In this thesis radical alkyne sulfonylation was chosen as the research topic,and two new protocols were developed for the preparation of sulfonyl-substituted cyclic compounds.The thesis includes three chapters.The first chapter is a literature review,in which the recent progress on alkyne sulfonylation reactions is introduced following the sequence of transition metal catalysis,non-metal catalysis,electrocatalysis and visible light catalysis.The second and third chapters describe the research conducted during the master's study,which is summarized below:(1)By using Ir[(dF(CF3)ppy)2(5,5'-d(CF3)bpy)]PF6 as the photocatalyst,sodium sulfinate as the sulfonyl source,N-iodosuccinimide(NIS)as an iodine source,a three-component reaction of the alkynes was realized.The reaction provides a simple,effective method for the preparation of 5-sulfonylmethylenepyrrolidin-2-ones.(2)Tandem radical sulfonylation/cyclization of alkynes was developed by using two different photochemical protocols.The first one uses Ir[(ppy)2(bpy)]PF6 as photocatalyst and sodium sulfinates as the sulfonyl radical precursors.The second one uses Cu(dap)2Cl as photocatalyst and sulfonyl chlorides as the sulfonyl radical precursors.These reactions can be applied to the preparation of sulfonyl-substituted cyclopentane compounds... |
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