The Research Of The Reaction On K₂S₂O₈ Mediated Cyclo-addition Of Conjugated Amide And Decarboxylative Coupling Of Conjugated Acid

As the development of organic synthesis,transition metal-free catalysis gradually became a hot point of organic research in recent period of time.Compared to the condition of transition metal catalyzed coupling reactions,transition metal free catalysis has incomparable advantages,such as:low toxicity,environmental friendly,economic efficiency and good chemical selectivity,etc..The progress and ascension of these new methods provide a strong motivation for the development of organic chemistry.Therefore,developed the transition metal-free catalytic conditions on organic chemistry,or pharmaceutical synthesis of industrial application has immeasurable importance,this not only conforms to the interests of the sustainable development strategy put forward by the state,but also provides a better understanding of how to perform a chemical conversion whether or not under the condition of transition metal catalysts.In view of the above,and also combined with some of the important work in our laboratory,we mainly studied K2S2O8 promoted addition-cyclization of N-methyl-N-arylacrylamides with arylaldehydes or benzenesulfonohydrazides,and oxidative decarboxylative cross coupling of acrylic with cyclic ethers under air conditions,the main contents are as follows:(1)this paper reviewed the transformation of acrylamide and acrylic acid with various types of research progress under the transition metal free conditions,and elaborated the research significance,the purpose of this paper and the main content.(2)the phenylacylation of aryl acrylamide was studied systematically.We firstly employed N-methyl-N-phenylmethacrylamide and p-methoxybenzaldehyde as model substrates to optimise the reaction conditions,and then get the best reaction conditions:N-methyl-N-phenylmethacrylamide(0.2 mmol),p-methoxybenzaldehyde(1.2 equiv),K2S2O8(3.0 equiv),tetrabutyl ammonium iodide(20 mol%)and methylene chloride(2.0 mL),120 ?,24 h,nitrogen(1 atm).In this reaction,we mainly investigated the applicability of aromatic acrylamide and aldehydes.The result shows that various acrylamide compounds with strong electron-withdrawing or strong electronic groups can be applied to the transformation,at the same time,we have successfully converted part of aldehyde compounds containing various substituents into desired products.(3)the benzene sulfonylation of aromatic acrylamide was studied systematically.1 On the basis of our investigation and optimization of the phenylacylation of aryl acrylamide,the catalyst,reaction temperature and time conditions were optimazed later,and the optimal reaction conditions are as follows:N-methyl-N-phenylmethacrylamide(0.2 mmol),benzenesulfonohydrazide(1.2 equiv),K2S2O8(3.0 equiv),tetrabutyl ammonium iodide(20 mol%)and methylene chloride(2.0 mL),60 ?,24 h,nitrogen(1 atm).The substrate applicability of aromatic acrylamide and benzene sulfonyl hydrazine were investigated in this optimal reaction condition.The results showed that the functional group compatibility of the two types of substrate were very good.(4)the systematic study of the decarboxy coupling reactions between acrylic and cyclic ether compounds have been conducted.Reaction conditions were studied and optimized.We mainly examined the oxidant,the influence of reaction temperature and time of reaction,the final response for best conditions is:cinnamic acid(0.3 mmol),tetrahydrofuran(2 mL),K2S2O8(2.0 equiv),110 ?,24 h,air(1 atm).This reaction was investigated under the condition of transition metal free conditions:The applicable scope of the results showed that most of the acrylic acid compounds and cyclic ethers compounds can be transformed into desired products successfully,but the compatibility of the linear ethers compounds are not ideal.This paper studies the mechanism of aromatic acrylamide addition reaction and acrylic decarboxylation process.Based on the control experiments,the results analysis,and related literature works,we proposed a possible mechanism of the aromatic acrylamide addition-cyclization reaction and acrylic acid decarboxylation oxidation coupling reaction.