Q6(a)(i). Products and intermediates of two reductions
Elucidate the structure of the product and the intermediate (if any) in the following reactions: (A) the (S)-acid ester with 1) BH₃, 2) H⁺; (B) (E)-3-cyclohexylpropenal with NaBH₄. (5 + 5 = 10 marks) [structures given in the paper]
Answer in brief
(A) (S)-4-methyltetrahydropyran-2-one via ethyl (S)-5-hydroxy-3-methylpentanoate; (B) (E)-3-cyclohexylprop-2-en-1-ol via the alkoxyborate.
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Coverschemoselective reductionboraneNaBH4lactonisationδ-lactoneallylic alcohol
All parts of Question 6
- 6(a)(i) Products and intermediates of two reductions10 marks
- 6(a)(ii) Role of NMO in catalytic dihydroxylation5 marks
- 6(b) Three numericals15 marks
- 6(c)(i) Benzene to fulvene by light5 marks
- 6(c)(ii) Quantum yield of photobromination5 marks
- 6(c)(iii) Photolysis of 4,5-dimethylhexan-2-one5 marks
- 6(c)(iv) A, B and C from the mixed ketones5 marks