The Construction Of Carbon-Carbon And Carbon-Hetero Bond Via Iron Catalyzed Radical Functionalization Of Alkenes

Free radicals were applied in industry,agriculture,medicine and biochemistry.In particular,the radical functionalization of alkenes has always been one of the hottest research topics in organic chemistry.In recent years,the transition-metal catalyzed functionalization of alkenes has been developed rapidly to construct carbon-carbon bond and carbon-hetero bond.Among them,C-H functionalization and difunctionalization of alkenes were of great importance to research.In this content,we developed the radical functionalization of alkenes catalyzed by inexpensive iron salts to construct various carbon-carbon bond and carbon-hetero bond.Firstly,an efficient FeCl₂-catalyzed cross-coupling of silanes with styrene and its derivatives using DTBP as oxidant for selective synthesis of vinylsilanes was developed.Vinylsilanes become important building blocks or starting materials in organic synthesis,which rely on their unique reactivity profile and low environmental impact.This method presented an inexpensive,non-toxic and environmentally benign catalytic system.Compared with the traditional Fe(CO)_X complexes catalyzed reactions for the synthesis of vinylsilanes,this approach was E-specific in good yields and the catalyst was cheap and commercially available.Next,a new iron-catalyzed intermolecular three-component trifluoromethyl-acyloxylation of styrenes was developed.Because of the excellent ability to promote the metabolic stability and lipophilicity of bioactive molecules,modification with a trifluoromethyl group has gradually evolved to become a routinely used method in the pharmaceutical,agrochemical,and functional materials fields.Compared with other trifluoromethylating reagents,CF₃SO₂Na was an ideal trifluoromethyl source because of its safety and stability,low toxicity and low expense.Benzoic acids were cheap and easily available acyloxylating reagent and were widely applied in synthetic chemistry.Therefore,a series of ester-containing organofluorine compounds have been synthesized with the two components and alkenes catalyzed by iron salts,and various benzoic acids provided the products in 82%to 93%yields,which would be of great significance for organic synthesis and pharmaceutical chemistry.Finally,the three-component difluoalkylation of alkenes catalyzed by iron-facilitated photoredox has been developed.The carbon-carbon bond and carbon-hetero bond were simultaneously constructed smoothly.Ethyl difluoroacetate was a source of difluorinated moieties and compounds containing it were extensively applied for the synthesis of pharmaceuticals,agrochemicals,and enzyme inhibitors.Sulfur-containing organofluorine compounds have been successfully prepared by“one-pot”method from alkenes,thiols and Br CF₂CO₂Et using photocatalyst and FeCl₂ as the cooperative catalyst,exhibiting a broad substrate scope of thiols with about 90%yields.Meanwhile,difluoalkyl-containing amines compounds were key structural motifs in pharmaceuticals and functional materials and important building blocks in organic synthesis due to their unique bioactivities and chemical properties.Therefore,the difunctionalization of alkene with Br CF₂CO₂Et and amines was further studied.The fluorine-containing amines compounds were synthesized smoothly by photocatalyst and FeCl₂ cooperative catalysis.