📚 Organic Synthesis | 有机合成
Organic synthesis is the process of designing and carrying out a sequence of reactions to convert simple starting materials into a target molecule. In Cambridge A-Level Chemistry, you are expected to use your knowledge of functional group reactions, reagents and conditions to plan practical multi-step routes and evaluate alternative pathways.
有机合成是设计并实施一系列反应、将简单起始原料转化为目标分子的过程。在剑桥 A-Level 化学中，你需要运用官能团反应、试剂和条件的知识，规划可行的多步路线，并评价不同合成途径。
1. The Aim of Organic Synthesis | 有机合成的目标
In an organic synthesis problem, you are usually given a starting material and a target molecule. The target may contain a different functional group, a longer carbon chain, or a different carbon skeleton. Your job is to choose a series of reactions that converts the starting material into the product with the fewest possible steps and sensible reagents.
在有机合成问题中，通常给出起始原料和目标分子。目标分子可能含有不同的官能团、更长的碳链或不同的碳骨架。你的任务是选择一系列反应，以尽可能少的步骤和合理的试剂将起始原料转化为产物。
A successful route must consider reaction yield, side reactions, availability of reagents and reaction conditions such as temperature, solvent and catalyst. For example, a route that requires many separate purification steps is less efficient than a direct one.
一条成功的路线必须考虑反应产率、副反应、试剂可得性以及温度、溶剂和催化剂等反应条件。例如，需要多次分离纯化的路线比直接路线效率低。
Chemists often use retrosynthesis — working backwards from the target to a simpler starting material. This helps identify the key bond-forming steps before planning the forward route.
化学家常用逆合成分析法——从目标分子逆向推导到更简单的起始原料。这有助于在规划正向路线前确定关键的成键步骤。
2. Functional Group Interconversion Toolkit | 官能团转化工具包
A large number of synthesis problems can be solved by recognising that one functional group can be converted into another. The list below summarises the most common conversions required at AS and A2 level.
大量合成问题可以通过识别一个官能团能转化为另一个官能团来解决。下表总结了 AS 和 A2 阶段最常见的重要转化。
- alkane → halogenoalkane: X₂, UV light, free-radical substitution | 烷烃 → 卤代烷：卤素、紫外光、自由基取代
- halogenoalkane → alcohol: NaOH(aq), heat under reflux | 卤代烷 → 醇：氢氧化钠水溶液，回流加热
- halogenoalkane → nitrile: KCN in ethanol, heat under reflux | 卤代烷 → 腈：氰化钾乙醇溶液，回流加热
- halogenoalkane → amine: excess NH₃ in ethanol, heat | 卤代烷 → 胺：乙醇中过量氨，加热
- halogenoalkane → alkene: KOH in ethanol, heat, elimination | 卤代烷 → 烯烃：氢氧化钾乙醇溶液，加热，消除
- primary alcohol → aldehyde: K₂Cr₂O₇/H₂SO₄, distillation | 伯醇 → 醛：酸性重铬酸钾(VI)，蒸馏
- primary alcohol → carboxylic acid: K₂Cr₂O₇/H₂SO₄, reflux | 伯醇 → 羧酸：酸性重铬酸钾(VI)，回流
- aldehyde → primary alcohol: NaBH₄ in water/ethanol | 醛 → 伯醇：NaBH₄ 水/乙醇溶液
- aldehyde → hydroxynitrile: HCN, trace base | 醛 → 羟基腈：氰化氢，微量碱
- carboxylic acid → ester: alcohol, concentrated H₂SO₄, heat | 羧酸 → 酯：醇、浓硫酸、加热
- acyl chloride → amide/ester: nucleophilic addition-elimination | 酰氯 → 酰胺/酯：亲核加成-消除
- nitrobenzene → phenylamine: Sn
Published by TutorHao | A-Level Chemistry Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导Cancel reply