碱引发下全卤代烷之间的卤素交换反应研究

利用碱的亲卤进攻,既可引发一些含溴与含氯全卤代烷之间进行溴-氯交换反应,也可引发单个含溴、氯全卤代烷进行自身的溴-氯交换反应.此卤素交换反应条件温和,为全卤代烷的合成提供了一条新的途径.并对交换反应的机理进行了初步地探讨,认为反应主要是经由碱的亲卤进攻引发产生碳阴离子中间体后,多步碳阴离子与全卤代烷之间的亲卤进攻的机理所进行的,各种交换产物的量是这种多步交换反应达到平衡后的结果.     

Aggregation of deuteroporphyrin IX diesters in aqueous-organic binary solution

The aggregation properties of a series of deuteroporphyrin IX diesters in the THF-Buffer (0.1 mol L-1 Tris-HCl) aquiorgano solvent have been studied by means of UV-Vis and fluorescence spectrometers.Experimental data show that the dimerization of porphyrins is mainly determined by π-πinteraction in pure organic solution while further aggregation of porphyrins with long hydrocarbon chains is more likely driven by hydrophobic-lipophilic interaction in aqueous-organic binary solution.The appearance of the aggregates induces a red shift in absorption spectra and fluorescence quenching in fluorescence spectra.The chain-length effect and chain-foldability effect have also been observed.     

Base initiated halogen-exchange reactions between perhaloalkanes

Halophilic attacks on C-X bonds (X=Br,Cl) by a base can easily initiate mtermolecular bromme-chlonne exchange reactions either among bromine-or chlorine-containing perhaloalkane molecules of different compounds of among molecules of the same compound It provides a new and convenient method to synthesize perhaloal-kanes Apparently,it pertains to an amomc mechanism,i e.the reaction is initiated by halophilic attack on C-X bonds by the base,and an intermediate carbanion is formed.Distributions of the products depend on the equilibria involving all carbanion intermediates and perhaloalkane product molecules.     

Relative reactivities of halogen-substituted substrates (R-Br,R-C1) toward the halophilic attack by a carbanion

Relative reactivities of bromine-substituted substrates (R-Br) or chlorine-substituted substrates (R-CI) toward bromophilic or chlorophilic attack by a carbanion have been evaluated by the intermolecular competition kinetics. Relative reactivity orders are CF3CFBr2 >CF3CBr3≥CBr4 > CHBr3 > CF3CFBrCF2Br > CF2Br2 > BrCF2CF2Br > BrCH2CO2Et≥ BrCF2CFHBr > CH2Br2 > BrCH2CH2Br, and CI3CNO2 > CI3CCN > CI3CCOPh > cyclo-C5CI6> CI3CCOCI > CCI3CF2CI > CCI3CF3 ≥ CCI4 > CCI3CCI3 ≥ CCI3(CF2)2CI > CI3CCOCCI3 > CCI3(CF2)6CI > CI3CCO2Et > CI3CF > CI3CPh>CI3CCH2O2CCH3.     

碳负离子对卤代化合物的相对亲卤反应活性研究

通过分子间竞争动力学的方法, 揭示了一种碳负离子对一些溴代化合物或氯代化合物的亲溴或亲氯反应的相对活性, 其顺序为: CF₃CFBr₂ > CF₃CBr₃≥CBr₄＞ CHBr₃＞CF₃CFBrCF₂Br＞CF₂Br₂＞BrCF₂CF₂Br＞BrCH₂CO₂Et≥BrCF₂CFHBr＞ CH₂Br₂＞BrCH₂CH₂Br, 和Cl₃CNO2＞Cl₃CCN＞Cl₃CCOPh＞cyclo-C₅Cl₆＞Cl₃CCOCl＞CCl₃CF₂Cl＞CCl₃CF₃≥CCl₄＞CCl₃CCl₃≥CC₁₃(CF₂)₂Cl＞Cl₃CCOCCl₃＞CCl₃(CF₂)₆Cl＞ Cl₃CCO₂Et＞Cl₃CF＞Cl₃CPh ＞Cl₃CCH₂O₂CCH₃.     

Ph3P/CF3CCl3作为一个新的羰基烯烃化试剂的研究—一锅法合成烯烃RCH=CClCF3

Ph3P/CF3CCl3与醛在室温下一锅反应生成三氟甲基取代的烯烃RCH=CClCF3(3). 芳香醛及α,β-不饱和醛的反应显示高度立体选择性, 给出Z式异构体. 而饱和脂肪醛的反应立体选择性较低, Z与E式异构体的比例为2:1至3:1. 反应可能是经由叶立德Ph3P-CClCF3的Wittig型反应. 本工作表明, Ph3P/CF3CCl3可以作为在十分温和的条件下向有机分子中引入=CClCF3结构单元的方便试剂.     

烯胺与全卤代氟卤乙烷的亲卤反应研究——一种β-CF_3取代的α，β不饱和酮的合成法

在无引发剂或紫外光照的情况下，烯胺能与CF_3CXYZ(X,Y,Z=Cl, Br)进行自发 的反应，得么以Z-式异构体为主的 β-CF_3取代的 α，β不饱和酮，产率为50%左 右。反应可能是经由电子转移引发的自由基型机理进行的。     

二-(1-甲基-1-七氟异丙基)五氟丙基过氧化二碳酸酯的合成

报道了一个可能的自由基前体——二-(1-甲基-1-七氟异丙基)五氟丙基过氧化二碳酸酯(1)的合成方法及其特性. 以全氟2-甲基-3-戊酮(2)为原料, 与甲基碘化镁反应后所得到的醇再与光气进行氯甲酰化反应, 随后与过氧化钠的过氧化反应后, 以17%的总产率首次合成了目标化合物.     

β-Oxido膦叶立德的亲卤反应: 一种便利地合成三取代卤代烯 烃的方法

β-Oxido膦叶德作为新核试剂对一系列全卤代烷烃中的碳卤键能顺利地进行新卤进攻,生成α-卤代betaine中间体,并由此直接转化成相应的以Z式构型为主、反应产率中等的氯代、溴代或碘代的三取代烯烃。利用不同结构的鏻盐和醛缩合而? 傻摩?Oxido膦叶立德与全卤代烷反应,可以方便地合成一系列不同的结构的三取? 贝┨? $601$Aβ-OxidophosphoniumylidesasnucleophilesreactreadilywithvariousperhalalkanesviahalophilicattackonC—X(X=I,BrorCl)bondstoformaα-halosubstitutedbetaineintermediates,whichcanbetransformedinsituintoZ-isomersofchloro-,bromo-oriodo-substitutedolefinsasmajorproductsingoodyields.Thesenovelreactiosnmayaffordafacileroutetovarioustrisubsitutedhaloolefinsbymeansofβ-Oxidophosphoniumylidespreparedinsitufromvariousphosphoniumsaltsandaldehydes.