Studies On The Photoinduced Free Radical Carbonylation Of Olefins

Olefins are important raw materials and precursors in organic synthesis,and have a wide range of applications in the fields of material chemistry,petrochemicals and biomedicine.Therefore,the functionalization of olefins has always been one of the hotspots in modern organic chemistry synthesis.The functionalization reactions of olefins usually include addition reactions,polymerization reactions,redox reactions,and carbonylation reactions,etc.,so more products with complex structures and diverse properties can be obtained.Among them,olefin carbonylation is generally catalyzed by transition metals,and carbon monoxide(CO)is used to introduce carbonyl groups into the substrate.This type of reaction usually has the advantages of high atom economy and step economy.With the continuous deepening of the concept of sustainable development,the strategy of free radical carbonylation with the advantages of environmental friendliness and simple operation has emerged.Based on previous studies,this thesis explored the carbonylation reaction of olefin radicals induced by visible light.It is mainly divided into the following two parts.First,the visible light-induced free radical carbonylation reaction of olefins and CO was studied.In the reaction,N-alkoxypyridinium salt was used as oxygen radical precursor and oxidant to initiate free radical reaction under visible light irradiation,and a series ofα,β-unsaturated ketones were obtained with high yield.The process does not require a metal catalyst,and the olefin carbonylation can be realized only under room temperature conditions,and the operation is simple,and the reaction conditions are relatively mild,which is suitable for the carbonylation of various olefins and alkanes.In this paper,through comparative experiments and deuteration experiments,a possible catalytic cycle mechanism is proposed.The C-H bond in alkanes can be directly activated,which has application value.Secondly,the free radical carbonylation reaction of olefin and formate induced by visible light was studied.Based on the research of the first part of the work,the greener alkyl formate was used instead of CO as the carbonylation reagent,and a series of α,β-unsaturated esters with good regioselectivity and E selectivity were obtained.The reaction raw materials are easily available,the conditions are mild,and the reaction has good tolerance to various functional groups.Compared with the carbonylation reaction involving gas CO,this process does not require a special high-pressure reaction device,which not only helps reduce equipment costs and energy consumption,but also improves the safety of the experiment.This paper also explored the reaction mechanism and proposed a possible catalytic cycle process.