(8) 3.3. Propose mechanisms for the following reactions: HO COOEt (2) a Eto . EtOH HNHO b) H (4) (2) c) H N O [11 marks] QUESTION 4 (7) 4.1. The natural product nuciferal was synthesized by the route summarized here. CHO OH BrMg 0 Step1 Step 2 Step 3 CHO 0 Step 4 A (a) Suggest a synthesis of the starting material A from an a.-unsaturated aldehyde and dialcohol (2) (b) Suggest reagents for each step. (3) (c) Draw out the retrosynthetic analysis giving the disconnections that you consider the planners had in mind and label them suitably. (2) (4) 4.2. Predict the products that would be formed in these reactions H 1. EtMgBr? (2) a) 2.Ph,CO 1. Mg, THE ? (2) 3 b) Br 2. O 3. F.H.0