Electrochemically Induced Alkyne Functionalization Reaction

Alkynes and their derivatives are widely found in nature and play an important role as basic raw materials in organic synthetic chemistry.A series of bonds,such as C-C,C-O,C-N and C-X bond,can be formed through the functionalization of alkynes,these new bonds can be furtherly converted into other valuable compounds.For a long time,activation of the carbon-carbon triple bond of alkynes and introduction of various functional groups into alkynes have been extensive studied.On the other hand,as people become more and more aware of the importance of environmental protection,functionalization of alkynes without metal participation is favored by more chemists.Electrochemical synthesis have been widely used in the synthesis of various compounds recent years due to its advantages of cleanliness,high efficiency,green and environmental benign.In this thesis,we designed the electrochemically triggerd functionalization of alkynes to prepare important organic intermediates: α-bromoketones andα,α-dibromodimethyl ketals.The whole paper is divided into two parts,briefly described as follows:Part I: Electroche mically triggered difunctionalization of alkynes for synthesis of α-bromoketonesThe difunctionalization of alkynes for synthesis of α-bromoketones,which can sever as an important class of organic intermediates,was realized by radical addition and single electron transfer under constant voltage in this procedure.A series of target products were synthesized with low cost inorganic salt potassium bromide(KBr)as bromine source and electrolyte in good yield.Overall,the strategy was operationally safe and enviromentally friendly,which provide a new route for the s ynthesis of α-bromoketones.Part II: Electroche mically triggered polyfunctionalization of alkynes for synthesis of α,α-dibromodimethyl ketalsIn this process,methanol and potassium bromide were respectively used as bromine source and methoxyl source under electrochemical induction.And then two C-Br bonds and two C-O bonds were successfully constructed by addition of bromine and methoxy to the carbon-carbon triple bond of alkynes,achieving the polyfunctionalization of alkynes.Compared to other similar reports,this reaction was benefited from easy to handle,simple raw material and green environmental benign,and providing a new access to the polyfunctionalization of alkynes.