Q2(c)(i). Bromolactonisation of endo-norbornene-carboxylic acid
What product can one expect from the following reaction? Depict the stereochemical outcome at every step.
Answer in brief
The product is the bromolactone: Br exo on C-5, lactone O endo on C-6 (C₈H₉BrO₂, racemic), i.e. exo-5-bromo-endo-6-hydroxynorbornane-endo-2-carboxylic acid γ-lactone, formed by exo bromonium formation and anti, endo opening by the carboxylate.
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Coversbromolactonisationexo faceexo bromonium ionendo facefive-membered γ-lactone
All parts of Question 2
- 2(a)(i) (S)-2-Bromobutane with HCOOH and with HCOO⁻Na⁺/DMSO5 marks
- 2(a)(ii) 7-Norbornyl and anti-7-norbornenyl tosylates: participation of a C=C5 marks
- 2(b) E2 in a locked trans-decalin and in locked 1,2-dibromocyclohexanes10 marks
- 2(c)(i) Bromolactonisation of endo-norbornene-carboxylic acid5 marks
- 2(c)(ii) Octalin to the tertiary and the secondary decalol5 marks
- 2(d) Aromatic character of sydnones10 marks