Investigations On The Oxidation Reaction Of The Organoboron Compounds Via Visible Light Photocatalysis

Recently,visible light has attracted more and more attention because of its abundant resource,easy availability,green economy and etc.The photocatalysis not only can perfectly utilizes visible light,but also has mild and efficient reaction conditions,which has obvious advantages and wide application prospects compared with traditional organic synthesis methods.Organoboron reagents bearing the characteristics of low toxicity,relative stability and functional group tolerance can realize the transformation of various functional groups and have important application value in organic synthesis.If the photocatalysis systems replace the traditional catalytic systems such as transition metal catalysis and acid or base catalysis to develop new coupling reactions of organic boron reagents,the research will have a certain scientific significance and application value both in medicinal chemistry and biochemistry.Among these organoboron compounds,organoborate salts and organoboric acids are of particular interest.Thus,in this paper the catalysis oxidation and transformation of organoboron reagents?potassium organotrifluoroborate,organoboric acid and esters?under the visible light photoctalysis was mainly studies and discussed.The dissertation is consisted of three chapters:The first chapter is a review of organoboron reagents.Although organic boron reagents have been widely used in organic synthesis,there are merely few progress made recently in the research under photocatalytic conditions.So in this chapter,the coupling reaction study of organoboron reagents in recent years by visible light photocatalysis is mainly reviewed.The second chapter elaborates that utilizing Ir[dF?CF₃?ppy]₂?dtbbpy?PF₆ as photocatalyst,carbon radical was generated from potassium organotrifluoroborate under the irradiation of visible light and coupled with Morita-Baylis-Hillman adduct derivatives?MBHADs?subsequently.MBHADs are widely used in carbon-carbon bond forming reactions due to simple starting materials,mild reaction conditions,high atom economy and good flexibility for further conversion.However,there are very few nucleophilic reactions by free radicals.Therefore the reaction of MBHADs and potassium organotrifluoroborate via visible light photoctalysis was focused,which provided a photocatalytic process for the preparation of trisubstituted alkenes.The third chapter discussed the Lewis base enhancing the reactivity of p orbitals of the boron atom under the similar conditions and the catalytic oxidation of the organic boronic acid?ester?for preparing a similar type of products was investigated,which is difficult to be oxidized under ordinary photocatalytic conditions.In addition,MBHADs could be also activated by Lewis bases,and thus allylic nucleophilic reactions may occur.However,to our surprise,only the target products was formed under this reaction condition.This method not only expands the organoboron reagents which is originally few applied in the photoredox reaction,but also has a broader scope of the substrates.