Cobalt-catalyzed ?-C-H Functionalization Of Ketones And Visible Light Promoted S?H Functionalization Of Thiophenols

C?H Functionalization represents an atom-and step-economic approach to construct valuable complex organic molecules in modern organic synthesis.C?sp³??H Bond has high bond energy,low reactivity,and difficulty in activation,it is difficult to be efficiently converted.Therefore,the activation of C?sp³??H bond has become a main challenging in organic synthesis.Methanol is widely used as one of the most basic industrial chemicals.It is often used as a“green”and“renewable”C1 source to achieve various transformations in organic synthesis.Visible light is an ideal energy of chemical reactions because of the characteristics of large natural abundance,renewable and clean.In recent years,the research on visible light photocatalytic reaction has made great breakthroughs and has developed into a practical method and powerful tool in organic synthesis.Based on the full investigation and aimed at the research status of?-C?H functionalization of ketones and S?H functionalization of thiophenols,the?-C?H functionalization of ketones with methanol as C1 source and the visible light promoted S?H functionalization of thiophenols have been studied in this thesis.The main research contents of the thesis include the following two partsPart I:Cobalt-catalyzed?-methoxymethylation and aminomethylation of ketones using methanol as a C1 building blockUsing methanol as C1 source,cobalt-catalyzed?-methoxymethylation and?-aminomethylation of ketones have been developed.With cheap CoCl₂·6H₂O as catalyst,the methoxymethylated products were obtained in up to 91%yield.Based on the observed reversibility of methoxy adduct to enone,the?-aminomethylation of ketones was then achieved.The new method has the advantages of free of expensive transition metal catalyst,mild reaction conditions and broad scope of substrates.Part II:Visible light promoted S?H insertion reaction of thiophenols into?-diazo estersUsing?-diazo ester as the carbene precursor,we have developed a visible-light promoted S?H insertion reaction of thiophenols.The reaction was directly irradiated under visible light at room temperature to construct C?S bond efficiently.The established reaction method does not use of any metal catalyst,photocatalyst and additive,and possesses the merits of mild conditions,high yield and wide substrate scope.It provides a green and novel approach to construct C?S bond via the S?H insertion reaction.