Kinetic Study of the Addition of Trihalides to Unsaturated Compounds in Ionic Liquids. Evidence of a Remarkable Solvent Effect in the Reaction of ICl<sub>2</sub><sup>-</sup>
作者:Cinzia Chiappe、Daniela Pieraccini
DOI:10.1021/jo049318q
日期:2004.9.1
while the hydrogen bonding ability of the imidazolium cation is probably the main factor able to increase the rate of the addition of ICl2- to double and triple bonds, this property has no effect on the electrophilic addition of Br3- to alkenes and alkynes. Furthermore, in the case of the ICl2- reaction, the hydrogen bonding ability of ILs can be exploited to suppress the unwanted nucleophilic substitution
Bromochlorination of Alkenes with Dichlorobromate (1−) Ion. IV. Regiochemistry of Bromochlorinations of Alkenes with Molecular Bromine Chloride and Dichlorobromate (1−) Ion
作者:Takeshi Negoro、Yoshitsugu Ikeda
DOI:10.1246/bcsj.59.2547
日期:1986.8
The regioselectivity of the addition of molecular bromine chloride to alkenes is dependent on both the steric and electronic effects of the alkyl substituent. In contrast, the regioselectivity of the addition of dichlorobromate (1−) ion to alkenes is controlled mainly by the steric effect of the substituent.
[V12O32]4− (V12), possesses a 4.4 Å cavity entrance, and the cavity shows unique electrophilicity. Owing to the high polarizability, Br2 was inserted into V12, inducing the inversion of one of the VO5 square pyramids to form [V12O32(Br2)]4− (V12(Br2)). The inserted Br2 molecule was polarized and showed a peak at 185 cm−1 in the IR spectrum. The reaction of V12(Br2) and toluene yielded bromination of toluene
十二烷酸酯,[V 12 O 32 ] 4−(V12),具有4.4Å的腔入口,腔显示出独特的亲电性。由于高极化率,Br 2被插入到V12中,引起VO 5方锥之一的倒置以形成[V 12 O 32(Br 2)] 4-(V12(Br2))。插入的Br 2分子被极化,并且在IR光谱中的185 cm -1处显示一个峰。V12(Br2)与甲苯的反应在环上产生了甲苯的溴化反应,显示出插入的Br 2的亲电性分子。化合物V12(Br2)也与丙烷,正丁烷和正戊烷反应生成溴化烷烃。在单溴戊烷产品中,用V12(Br2)溴化显示出对3-溴戊烷的高选择性(64%),在2,,3-二溴丁烷和2,3-二溴戊烷中具有较好的苏式异构体。独特的无机空穴陷阱Br 2导致双原子分子极化。由于其新的反应场,被捕集的Br 2显示了烷烃的选择性官能化。
Outer-sphere and inner-sphere processes in reductive elimination. Direct and indirect electrochemical reduction of vicinal dibromoalkanes
作者:Doris Lexa、Jean Michel Saveant、Hans J. Schaefer、Su Khac Binh、Birgit Vering、Dan Li Wang
DOI:10.1021/ja00173a002
日期:1990.8
The reduction of vicinal dibromoalkanes is investigated as an example of the dichotomy between outer-sphere and inner-sphere processes in reductiveelimination. As a result from the analysis of the kinetic data, outer-sphere reagents such as carbon electrodes and aromatic anion radicals react with vicinal dibromoalkanes according to an «ET» mechanism in which the rate-determining step is a concerted