1. Answer ALL parts. (a) Answer BOTH parts (i) and (ii). (1) Draw structures of all possible enolate ions formed by treatment of each of the following with a suitable base. M & Br (ii) Suggest, with reasoning, which enolate ion predominates, at equilibrium, in each case. (12 marks) (b) Answer All parts (1), (ii) and (iii). Reaction between ketone 1 and benzaldehyde 2, in the presence of aqueous NaOH, affords A (CsHs0). CHO NaOH(aq). C15H180 CgH140 1 z 2 (i) Suggest a structure for A. (ii) Provide a "curly arrow" mechanism for the formation of A, indicating which step is essentially irreversible under these reaction conditions, (iii) Reaction between 1 and 2 in the presence of NaOH in an excess of D:0 affords B (CisHD.0). With explanation suggest a structure for B. CHO NaOH B D20 CH5H6D20 CgH140 CyH60 2 (c) Answer All parts (i), (ii) and (iii). Reaction of aldehyde 3 with ester 4 in the presence of N-methylmorpholine 5 (a weak organic base) afforded C. Reduction of C to 6 was readily achieved using NaBH. (i) Suggest a structure for C. (ii) Provide a "curly arrow mechanism for the formation of C. (iii) Provide a "curly arrow mechanism for the reduction of C with NaBH4. CHO 5 N chrome CH3 'N CO2Et NO2 Cz1H18N206 CAH7NO4 C17H13NO3 3 4 CO2Et NO2 NaBHA / ETOH Cz1H20N206 6 (6 marks)