Let's break down the reactions step by step: **Step 1: Conversion of alcohol to tosylate** - Reagent: TsCl, pyridine - The alcohol group (OH) is converted to a tosylate (OTs), which is a good leaving group. **Step 2: Substitution with NaCN** - Reagent: NaCN - The tosylate group (OTs) is replaced by a cyanide (CN) group via SN2 mechanism. **Step 3: Hydrolysis of nitrile** - Reagent: H₂SO₄, H₂O - The nitrile (CN) group is hydrolyzed to a carboxylic acid (COOH). **Step 4: Reduction of carboxylic acid** - Reagent: 1. LiAlH₄ 2. H₂O - The carboxylic acid (COOH) is reduced to a primary alcohol (CH₂OH). **Step 5: Bromination** - Reagent: PBr₃, pyridine - The primary alcohol (CH₂OH) is converted to a primary bromide (CH₂Br). --- ### Structures in the boxes: #### Box 1 (After TsCl, pyridine) **Structure:** 2-Butyl tosylate CH₃-CH₂-CH(OTs)-CH₃ #### Box 2 (After NaCN) **Structure:** 2-Butyl nitrile CH₃-CH₂-CH(CN)-CH₃ #### Box 3 (After H₂SO₄, H₂O) **Structure:** 2-Butyl carboxylic acid CH₃-CH₂-CH(CO₂H)-CH₃ #### Box 4 (After LiAlH₄, H₂O) **Structure:** 2-Butyl primary alcohol CH₃-CH₂-CH(CH₂OH)-CH₃ #### Box 5 (After PBr₃, pyridine) **Structure:** 2-Butyl primary bromide CH₃-CH₂-CH(CH₂Br)-CH₃ --- ### Summary Table: | Step | Structure | |------|-------------------------------------------| | 1 | CH₃-CH₂-CH(OTs)-CH₃ | | 2 | CH₃-CH₂-CH(CN)-CH₃ | | 3 | CH₃-CH₂-CH(CO₂H)-CH₃ | | 4 | CH₃-CH₂-CH(CH₂OH)-CH₃ | | 5 | CH₃-CH₂-CH(CH₂Br)-CH₃ | Would you like me to draw the structures for you?