The Studies On Addition Of Free Radicale In Oxygen Centers And Cyclization Of Oxime Ester With 1,3-Dicarbonyl Compounds

Since the 1930 s,free radical chemistry has gradually led the synthesis of organic chemistry.It has become one of the most classical methods in organic synthesis chemistry.In recent years,with the transition metal catalysis,photocatalysis and electrocatalysis are in the ascendant.It has inJected new blood and power into the continuous development of free radical chemistry.However,due to the high activity of free radicals,the existence of a very short time,and poor chemical selectivity,it has brought great difficulties and challenges for chemists to study free radical chemistry.In this paper,the development of the addition reaction of unsaturated bonds(alkenes,alkynes,isocyanides,etc.)to free radicals is first briefly described.The addition reaction of oxygen radicals to isocyanides and transition metal-catalyzed reaction of O-acetylation aryl ketoximes with 1,3-dicarbonyl compounds are described in detail.Related research has mainly achieved the following results:1.Successfully demonstrated a method for the synthesis of amide compounds by the addition reaction of oxygen radicals to isocyanide.By this method,various valuable aryl carboxylic acid amides can be easily synthesized.In order to have a preliminary understanding of the mechanism of this reaction,some relevant mechanistic verification experiments and electron paramagnetic experiments(EPR)have also been done.From the preliminary mechanism study,it is known that the addition reaction of oxygen-centered radicals between aryl carboxyl radicals and isocyanides was confirmed,and finally the target product amide compound was obtained through intramolecular rearrangement transformation and elimination of carbon dioxide.2.By using a cheap copper catalyst as a catalyst to catalyze the radical ring-closure reaction of O-acetylarylketoximes with 1,3-dicarbonyl compounds,a new synthesis method of polysubstituted pyrrole compounds has been successfully developed.Mechanism studies have shown that the reaction is a free radical process,O-acetyl aryl ketone oxime reduction to generate nitrogen radicals,and then free radical addition to 1,3-dicarbonyl compounds,and finally the ring closure to obtain the target product.O-acetyl aryl ketone oxime is not only used as a material,but also as an internal oxidant,and does not require the addition of an equivalent amount of oxidizing agent,in line with the concept of green chemistry.