Difunctionalization Of Alkenes Using A C-H Oxidative Strategy

The C-H bond is the most basic and important chemical bond of an organic compound.The C-H bond has a short length and a high dissociation energy,which is conventionally considered to be an inert chemical bond.In the past decades,the selective control of the C-H bond reaction sites are very difficult for chemical researchers.In recent years,chemists have employed both the C-H bonds and the alkene difunctionalization to achieve new alkene difunctionalization through C-H oxidative radical functionalization reactions,which have been widely used in organic synthesis and industry.In the past decades,transition metal,such as palladium,rhodium,gold,ruthenium and platinum,catalyzed C-H oxidative radical functionalization and alkene functionalization has been significantly developed and played an imortant role in organic synthesis.The C-H oxidative radical functionalization and alkene difunctionalization reaction exhibited high regioselectivity in the synthesis of various useful compounds,including multi-sites functionalized products in one step,in high atom-and step-economy manner.This method is attracted considerable attention of chemical researchers because it is an important alternative to construct useful carbon centers,especially including quaternary carbon centers that are commonly found in many natural products,drugs,and biologically active molecules.However,these reactions require expensive transition metals,and the complex,harsh reaction conditions with lower yields.Therefore,the development of a low-cost,simple,mild,atom-economic,and environmentally friendly C-H oxidative radical reaction to initiate the difunctionalization of alkenes is still challenging and desirable.On the basis,this thesis mainly studies on the use of inexpensive transition metals(e.g.,copper,iron)to achieve C-H oxidation radical functionalization/alkene difunctionalization reaction.Under different inexpensive transition metal(e.g.,copper,iron)catalysis,the catalytic activity,selectivity,substrate scope and reaction mechanisms were discussed.The main contents of this paper include:(1)Recent progress of the alkene difunctionalization reaction relying on the of C-H oxidation radical transformations is described,including:i)the C-H oxidation radical functionalization/vinylamide difunctionalization reactions,ii)the alkene difunctionalization reactions via C-H oxidation radical functionalization and aryl migration cascades,iii)the C-H oxidation radical functionalization/alkene difunctionalization reactions using heteroatoms as the reaction partners.(2)Inexpensiveirontransitionmetal-catalyzedthere-component1,2-difunctionalization of aryl alkenes with aromatic C(sp~2)-H bonds and aldehydes by C-H oxidative radical functionalization was developed.The reaction enables the synthesis of various aryl ketone compounds using the ferrous chloride and di-tert-butyl peroxide system.The reaction feature simple conditions,lower-cost catalyst,excellent tolerance of substrates.We proposed a possible mechanism on the basis of the free radical capture experiments(3)An inexpensive copper transition metal-catalyzed 1,2-difunctionalization of aryl alkenes with aromatic C(sp~2)-H bonds and alkyl chlorides by C-H oxidative radical transformations.The reaction allows the arylalkylation of aryl alkenes by means of copper acetylacetonate and p-methoxytetrafluoroborate diazonium salt,affording a variety of halo-possessing organic compounds.Compared with the previously reported reactions of alkyl chlorides,the current reaction selectively cleave the C-H bond,not the C-Cl bond.