Functional group routes
Organic synthesis links functional groups through known reactions. Alkene → (HBr) halogenoalkane → (NaOH aq) alcohol → (Cr₂O₇²⁻/H⁺, distil) aldehyde → (reflux) carboxylic acid → (alcohol, H₂SO₄) ester. Halogenoalkane → (KCN, ethanol) nitrile → (H⁺/H₂O) acid or (LiAlH₄) amine. Carbonyl → (HCN) hydroxynitrile; (NaBH₄) alcohol. Alcohol → (conc. H₂SO₄, heat) alkene. To lengthen a chain by one carbon, use CN⁻. Plan backwards from the target, and give reagents and conditions for each step.
≈ 45 minMulti-step synthesis
A2 synthesis combines aliphatic and aromatic reactions. Key aromatic links: benzene → (conc. HNO₃/H₂SO₄) nitrobenzene → (Sn/HCl, NaOH) phenylamine → (NaNO₂/HCl < 10 °C) diazonium → (phenol/NaOH) azo dye, or (warm water) phenol. Benzene → (RCl/AlCl₃) alkylbenzene → (KMnO₄/OH⁻, heat) benzoic acid. Benzene → (RCOCl/AlCl₃) aryl ketone → (NaBH₄) secondary alcohol. Acyl chlorides make esters and amides. Plan by retrosynthesis, give reagents and conditions, and recognise each step's reaction type. Purify solids by recrystallisation and check purity by melting point.
≈ 50 min