20120529碳负离子.pptVIP

Chlorobenzene can be converted to phenol by heating it with aqueous sodium hydroxide in a pressurized reactor . Bromobenzene reacts with the very powerful base, in liquid ammonia 南京航空航天大学06 C-14 bromobenzene is treated with amide ion in liquid ammonia, the aniline that is produced between the 1 and 2 position. When the ortho derivative 1 is treated with sodium amide, the only organic product obtained is m-(trifluoromethyl)aniline. 4 3 说明了什么？ Carbanion 3 is more stable than 4 because the carbon atom bearing the negative charge is closer to the highly electronegative trifluoro- methyl group. [kɑ:b?nai?n] 1o 醇 2o 醇（R = H） 3o 醇 3o 醇 1o 醇（R = H） 2o 醇 六、格式试剂相关合成 1 反应活性： 酯与格氏试剂的反应*** p41 a.? 制两个R相同的叔醇。b. 甲酸酯与格氏试剂得对称二级醇。 快步骤 慢步骤 立即反应 Restrictions on the use of Grignard reactions 缩醛对碱、氧化剂、格氏试剂等都是稳定的，但在稀酸中易水解水解，得到原来的醛或酮。缩醛（酮）在合成上用保护羰基。 例 1： 分析： 分子内羰基将参与反应，应先保护。 合成： 醚键，碱性条件下稳定 缩酮水解，除去保护 例2 由苯及不大于四碳的有机物合成 分析： 合成： BrCH2CH2CH2CHO (CH3)2CCH2CH2CH2CH2OH OH HOCH2CH2OH 干 HCl BrCH2CH2CH2CH O O Mg 无水醚 CH3COCH3 H+ H2O H2 Ni P O BrMgCH2CH2CH2CH O (CH3)2CCH2CH2CH2CHO OH 3） 复旦 作业 Thank you for your attention * When ethyl acetate reacts with sodium ethoxide, it undergoes a condensation reaction. After acidification, the product is a β-keto esters , Condensations of this type occur with many other esters and are known generally as claisen condensation (克莱森缩合） 五 经典 碳负离子反应 1 The claisen condensation: β-keto esters [,?s?t?u?siteit] 2 Dieckmann 反应 1）对称二羧酸酯的 Dieckmann 缩合 分析前者按照酮酯缩合机理形成 后者是酮发生烯醇互变，烯醇与酯发生酯交换生成 复旦 3 Benzoin Condensation 安息香缩合 中科院02南大03 The benzoin condensation is a reaction between two aromatic aldehydes, particularly benzaldehyde. The reaction is catalyzed by a nucleophile such as the cyanide anion . This is a reversible reaction. The two aldehydes serve different purposes; one aldehyde donates a proton and one aldehyde accepts a proton. [benz?uin] Rearrangement of the intermediate results in polarity reversal of the carbonyl group. Proton transfer and elimin