中级有机20130425碳正离子讲课定稿幻灯片.pptVIP

中山05 -H2O H+ 1. Protonation of a hydroxyl group -H2O 2.Elimination of water to yield tertiary carbocation. H+ Resonance-stablized carbocation Deprotonation Phenyl with electron donor group move first 中山大学 03浙江 作业2 7. 邻氨基醇的亚硝酸重排 91 浙大南大山大 复旦大学 转移基团带一对电子从离去基团的背面进攻； 转移基团的构型保持不变。 所到达的原子发生构型转化。 在重排过程中转移基础团 和离去基团彼此处于反式。 作业1南大08中科大08 作业2 作业3 作业4 作业5 Reactions, alkenes: Addition of hydrogen (reduction). Addition of halogens. Addition of hydrogen halides. Addition of sulfuric acid. Addition of water (hydration). Addition of aqueous halogens . Dimerization. Alkylation. oxidation. Hydroboration-oxidation. Addition of free radicals. Polymerization. Addition of carbenes. Epoxidation. Ozonolysis Allylic halogenation Reactions of aromatic compounds Halogenation of benzene Nitration of benzene Effects of multiple substituents on electrophilic aromatic substitution Nucleophilic aromatic substitution * 五. Reactions of Carbocations 4)Rearrangement 3)Combination with a nucleophile 2)Elimination of a proton Addition to an unsaturated linkage OH- X- 亲核重排 亲电重排 自由基重排 重排反应 驱动力：形成更稳定的物种 Usually the rearrangement was classified by the electron property of the moving group, such as Nucleophilic rearrangement, Electrophilic rearrangement, Radical rearrangement, etc. Molecular Rearrangements: it refers those reactions in which the carbon skeleton or the position of functional group changed. The type of rearrengement 1, 2-H 迁移 1, 2-CH3 迁移 1. 亲电加成与亲电取代机理 P67　　 What is it Mar’s Rule?-----The addition of HX to an alkenes, the hydrogen atom adds to the carbon atom of the double bond which has the greater number of hydrogen atoms. In ionic electrophilic addition to an alkene, the electrophile always adds to the carbon-carbon double bond so as to form the more stable carbocation. 【解】 Reactions that involve racemization (外消旋化反应） The evidence indicates that electrophiles attack the πsystem of benzene to form a delocalized nonaromatic carbocation known as a σcomplex. The sigma complex r