The answer lies in the functional group of the target molecule.
Their lecturer, Professor Thompson, wrote a complex organic synthesis problem on the board and asked the students to work on it in pairs. The problem read: Chemsheets Organic Synthesis Problems Answers
Work backward from the target molecule. Example: Target = pentan-2-ol. Backward: pentan-2-ol comes from pentan-2-one (reduction with NaBH4 ). Pentan-2-one comes from butanenitrile + CH3MgBr (Grignard). Butanenitrile from 1-bromopropane + KCN . Start from propane. The answer lies in the functional group of
Before you even think about reagents, count the carbon atoms in your starting material versus your target product. Example: Target = pentan-2-ol
| Starting Material | Target | Reagents & Conditions (Chemsheets standard) | |------------------|--------|-----------------------------------------------| | Ethene | Ethane | H2 , Ni or Pt , 150°C | | Ethane | Bromoethane | Br2 , UV light (free radical substitution) | | Bromoethane | Ethanol | NaOH(aq) , heat under reflux | | Ethanol | Ethene | Conc. H2SO4 , 170°C (elimination) | | Ethene | 1,2-dibromoethane | Br2 in inert solvent (e.g., CCl4 ), room temp | | Benzene | Bromobenzene | Br2 + FeBr3 catalyst, room temp | | Bromobenzene | Benzoic acid | 1. Mg, dry ether (Grignard). 2. CO2 . 3. H3O+ | | Phenol | 2,4,6-tribromophenol | Br2(aq) , room temp (no catalyst needed) |