3. Answer ALL parts. (a) (b) (c) (d) (i) (ii) When molecule N is heated with...

 

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3. Answer ALL parts. (a) (b) (c) (d) (i) (ii) When molecule N is heated with a catalytic amount of strong base (sodium hydride), deprotonation occurs to form P, which cyclises as shown to give vinyl anion Q. Reprotonation of Q gives R, which then spontaneously rearranges to form S. HO N Et Et reprotonation catalytic base O Et R S -Et Et Et spontaneous Et Et Me Give the classification of the ring closure that forms N from P according to Baldwin's nomenclature. O The rearrangement of R to form S is a pericyclic reaction. Give the classification of this pericyclic reaction. Draw the curly-arrow mechanism for this reaction. Me S Carry out a retrosynthesis of N which leads to starting materials of five carbons or fewer. Then draw out the forward reaction specifying all necessary reagents. Me S Carry out a different retrosynthesis of S which leads to starting materials of seven carbons or fewer. (Your retrosynthesis must not use N as an intermediate). Then draw out the forward reaction specifying all necessary reagents. Give the structure of the product T formed in the following reaction: Et NaH -Et Et Et T [2 marks] [4 marks] [8 marks] [8 marks] [2 marks] 3. Answer ALL parts. (a) (b) (c) (d) (i) (ii) When molecule N is heated with a catalytic amount of strong base (sodium hydride), deprotonation occurs to form P, which cyclises as shown to give vinyl anion Q. Reprotonation of Q gives R, which then spontaneously rearranges to form S. HO N Et Et reprotonation catalytic base O Et R S -Et Et Et spontaneous Et Et Me Give the classification of the ring closure that forms N from P according to Baldwin's nomenclature. O The rearrangement of R to form S is a pericyclic reaction. Give the classification of this pericyclic reaction. Draw the curly-arrow mechanism for this reaction. Me S Carry out a retrosynthesis of N which leads to starting materials of five carbons or fewer. Then draw out the forward reaction specifying all necessary reagents. Me S Carry out a different retrosynthesis of S which leads to starting materials of seven carbons or fewer. (Your retrosynthesis must not use N as an intermediate). Then draw out the forward reaction specifying all necessary reagents. Give the structure of the product T formed in the following reaction: Et NaH -Et Et Et T [2 marks] [4 marks] [8 marks] [8 marks] [2 marks]

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