Study On Efficient Hydrolysis Of Haloalkynes To α-haloketones

Alkynes containing a carbon-carbon triple bond is a kind of important organic compounds,which is cheap,commercial available and easy to get to.They have usually been applied in organic synthesis and were involved in important organic transformation including the formation of C-O bonds,C-N bonds,C-X bonds.Therefore,deeply studies and development concerning on carbon-carbon triple bond-re lated learning still remained desrible.a-halomethyl ketones have attracted rising attention because of the various building blocks for the synthesis of biologically active heterocycle compounds and natural products.Moreover,some a-haloketones are biologically active molecules frequently used in medicine as drugs or diagnostic aids,like enzyme inhibitors.Many methods for synthesize a-haloketones have been reported with reactions of different halide reagents and ketones or alkenes.However,most of these systems have disadvantages such as environmentally hazardous halogen molecules,long reaction times,harsh reaction conditions or over-halogenation.In this paper,alkynes were chosen as raw materials to the synthesis of a-halomethyl ketones The main works are as following:1.This paper develops a new method to synthesize a-halomethyl ketones from haloalkynes in the ionic liquidl(HSO4)2-H2SO4 system at 70℃ for 2 hours.This method provides a simple and effective method to prepare the a-halomethyl ketones with the advantages of good yields,functional group compatibility,no metal catalysts and recyclable ionic liquid.2.With the optimal conditions in hand,we embarked on the evaluation of the substrate scope for this transformation and we synthesized 23 kinds of a-halomethyl ketones compounds,the yield of up to 94%.To our delight,this method was suitable for aromatic and aliphatic alkynyl bromides.Both electron-donating and electron-withdrawing substituents on the phenyl ring all afforded the corresponding products.In addition to alkynyl bromides,alkynyl chlorides and alkynyl iodides can be hydrated to the corresponding products in high yields as well.3.This paper develops a new method to synthesize a-halomethyl ketones from alkynes through Ce(SO4)2/acid co-catalyzed.We have examined the impact of kinds of cerium sources,Br(?)nsted acids and its amount,solvent and temperature respectively by establishing a model reaction using 1-Bromo-2-phenylacetylene as the substate,and obtained the optimum reaction conditions.The reaction proceeded efficiently in the presence of 5 mol%,(Ce(SO4)2)1.2 equiv H2SO4 in dichloromethane under 80℃ for 12 hours.We embarked on the evaluation of the substrate scope for this transformation and 28 species a-halomethyl ketones were obtained in good yields.