Difunctionalization Of Unsaturated Hydrocarbons With ?-carbonyl Alkyl Bromides

The difunctionalization reaction of unsaturated hydrocarbons is an important strategy for the construction of chemical bonds,such as carbon-carbon bonds,carbon-hydrogen bonds and carbon-heteroatom bonds,and has emerged as a powerful method for the synthesis of various organic compounds that has wide applications in the synthesis of natural products,and pharmaceuticals.The difunctionalization of unsaturated hydrocarbons has attracted ongoing interest of organic chemists due to its simple synthesis step,high atomic economy and low-cost of raw materials.In recent years,the difunctionalization reactions of olefins have been greatly developed;however,examples of olefin difunctionalization with alkyl halides are rare,and especially the visible light photoredox catalysis for olefin difunctionalization with a-bromocarbonyl compounds still remains a huge challenge.Available approaches of olefin difunctionalization with alkyl halides focused on the oxidative strategies by the copperoriron catalysis or under metal-free conditions.However,such oxidative strategies suffer from limited substrate scope and has=rsh reaction conditions(often reaction temperature>80?),and a security risk stemed from the use of peroxides.The visible light photoredox catalysis has the advantages of mild reaction conditions and simple operation steps.Therefore,it is necessary to develop the difunctionalization reaction of olefins with a-bromocarbonyl compounds by means of the visible light photoredox catalysis.The difunctionalization reaction of N-arylpropiolamides for the synthesis of spirocyclic compounds is a hotspot in the past few years.The spirocyclohexadienone derivatives are the core framework of many natural products,drugs,and organic functional materials,as well as serve as versatile synthetic intermediates in organic synthesis.However,the majority of the difunctionalization reactions with N-arylpropiolamides for accessing spirocyclic compounds rely on electrophilic ipso-cyclization.Accordingly,this dissertation mainly studies on the difunctionalization of alkenes and N-arylpropiolamides with a-carbonyl alkyl bromides.The contents of this dissertation are described as following:(1)In chapter 1,recent progress in the difunctionalization reactions of unsaturated hydrocarbons has been documented in detail.The contents include(i)advances of unsaturated hydrocarbons photocatalytic difunctionalization reaction with alkyl halides,and(ii)advances of transition metal catalyzed oxidative unsaturated hydrocarbons difunctionalization reaction via a free radical process.The mechanisms for the difunctionalization reaction of unsaturated hydrocarbons using visible light photoredox catalysis and transition metal radical catalysis were also described and discussed.(2)In chapter 2,the visible light-induced[Ir(ppy)3]-ctalyzed three-component 1,2-alkylarylation of styrene with a-carbonyl alkyl bromide and N-heterocyclic compounds was described.The reaction can be performed at room temperature and allows the construction of two new C-C bonds in a single reaction.Further,the strategy provides a mild and practical olefin 1,2-alkylarylation reactions that rely on the diverse different functional groups of 3-substituted indoles and the 2-substituted pyrrole.(3)In chapter 3,a new route to producing 3-alkyl spiro[4,5]trienones by nick el-promoted oxidative radical ipso-annulation of N-(p-methoxyaryl)propiolamides with a-carbonyl alkyl bromides using TBHP oxidant has been developed.The method enables the formation of three new C-C bonds through oxidativecle avage of the C-Br bond,ipso-cyclization and dearomatization cascades,and is a novel alkyne 1,2-difunctionalization to access the construction of spiro-[4,5] trienones.