Study On Synthesis And Conversion Of Alkenes With The Participation Of DMSO And DMF

Alkenes（including their derivatives）are common organic compounds and are vital raw materials and intermediates in organic synthetic chemistry.The C=C bond in alkenes could be converted into new linear compounds by substitution,oxidation and addition reactions.In the meantime,alkenes could participate annulation reactions with other compounds to get important ring compounds,such as pyridines,oxazoles,benzenes and so on.Therefore,how to achieve efficient synthesis of alkenes and the their further functionalization have gain much attention by organic chemists and have been widely studied.So far,a large number of works about synthesis,functionalization and annulation of alkenes have been reported,nevertheless,in search of new methods for the synthesis of alkenes and further research work on functionalization and annulation based on alkenes are still necessary.The main research contents of this thesis are as follows:1.The synthesis of simple aromatic alkenes from aromatic aldehydes and ketones with DMSO in Zn-KOH system was developed.This is the first time to transform C=O bond in aldehyde-ketone to C=C bond in alkenes by using DMSO as methylene reagent.After obtaining the optimal conditions through condition optimization,a series of aromatic alkenes were obtained in high yields and high stereoselectivity,including mono-substituted aromatic alkenes,1,1-diaryl-substituted alkenes andα-methyl aromatic alkenes.In addition,we also tried diethyl sulfoxide,synthesizing（E）-1,2-disubstituted styrenes.Finally,we proposed a possible mechanism for the reaction by reviewing the literature and designing a series of controlled experiments.2.The substitution of alkyl and aryl groups on the terminal carbon atom in the C=C bond of alkenes by the reaction between alkenes and DMSO in the Fe³⁺/H₂O₂system was developed,synthesized higher alkenes which owned more substituted group from lower alkenes which owned less group.For all we know,this is the first time to realize the direct methylation of alkenes based on DMSO as methyl reagent.After obtaining the optimal conditions through condition optimization,nearly 40products including di-,tri-and tetra-substituted products were regioselectively synthesized based on mono-,di-and tri-substituted alkenes as substrates.Both aliphatic and aromatic alkenes could participate in this reaction.Moreover,not only DMSO,there were also other three sulfoxides that could be applied to this reaction,including diethyl,dibenzyl and diphenyl sulfoxide.According to a series of control experiment and some references,the possible mechanism of the reaction was proposed.3.A method for the synthesis of ketones from alkenes,DMSO and di-tert-butyl peroxide by oxidative addition of C=C bond promoted by ferrous salts was developed.In this reaction,DMSO provided an methyl group and TBHP provided an oxygen atom.Firstly,the optimum conditions of the cyclization reaction were obtained through optimization experiments,then,a series of ketones were synthesized by using the reaction based on the optimal conditions,including propiophenone,and 3-alkyl ketone.Additionally,we also tried diethyl sulfoxide,synthesizing some phenyl propyl ketone.Finally,through a series of controlled experiments and literature,we proposed a possible mechanism.4.Two molecules of styrenes participated annulation with DMF to get3,5-diaryl-substituted pyridines in the presence of iodine and persulfate has been carried out.In this reaction,Two C=C bonds in two molecules of styrenes offered four carbon atoms,DMF as both N and C source devoted non-adjacent N and C atoms to pyridines.As far as we know,two simple C=C bonds participated synthesis of pyridines has not been reported.In addition,the contribution of non-adjacent N and C atoms to the ring by the DMF and the provision of an isolated N atom by the DMF were reported for the first time.A series of 3,5-diarylpyridine compounds,including symmetric and unsymmetric products,were obtained under optimal conditions.Finally,based on relevant literatures and results of some experiments,a plausible mechanism was proposed in this work,which may demonstrate how DMF provide both N1 and C4 sources.