Visible Light-catalyzed Reaction Of Sodium Sulfinate And Acid Chloride To Selectively Construct Thioesters And Disulfides

As a green and sustainable energy source,visible-light plays an important role in synthetic chemistry.Visible-light-catalyzed free radical reactions have been a kind of research hotspot in current synthetic chemistry research.In view of the high activity of free radical reactions,to effectively control the reaction path to achieve product selectivity,diversity green and efficient construction are important topics for the current free radical chemistry research.This thesis used sodium sulfinate and acid chloride as substrates to regulate the cross-coupling and self-coupling process of acyl radicals and sulfur radicals under the visible-light catalysis to realize the selective synthesis of thioesters and disulfides.The main research content and the results are obtained as follows:(1)For the development of a new method about Hantzsch ester(HEH)/organic base metal-free visible-light catalysis in green and efficient selective construction of thioesters,the HEH/organic base visible-light catalytic system was used to cross-couple the sulfur radicals and acyl radicals to realize the formation of C-S bonds and obtain thioesters.By using this method,29 cases of thioesters with good yields were successfully obtained and one case of all was the reaction product of sodium sulfinate and sulfonyl chloride compound.The corresponding reaction process was researched by free radical capture,UV-Vis,CV and the control experiments.The reaction conditions of this method possess mild,high-efficiency,convenient operation.This reaction does not require high-energy ultraviolet light and additional photocatalysts,such as transition metal complexes and dyes.The substrate with a wide range of applications was easily obtained and cheap.It provided a green and efficient method for the synthesis of thioesters.(2)For selective construction of disulfides,a new method was designed and developed by coupling of visible-light and titanocene complexes.Under visible-light irradiation,titanocene(?)complexes was obtained based on reduction of photoexcited titanocene(?)complex by reductive quenching with N,N-Diisopropylethylamine(DIPEA).The cross-coupling process of sulfur radicals and acyl radicals was hindered due to the existing of titanocene(?)complexes in the system and the process of selfcoupling of sulfur radicals was promoted to produce disulfides.Various methods such as ESI-MS,free radical capture and the control experiments were used to research the reaction mechanism.This method is green and environmentally friendly.Meanwhile,it is beneficial to further study the selective coupling of free radicals and expand the application of titanocene in the field of photocatalysis.