Q3(b). Steric control of Diels–Alder reactivity
Compare 2,3-di-tert-butylbuta-1,3-diene A and 1,3-di-tert-butylbuta-1,3-diene B as Diels–Alder dienes.
Answer in brief
A is strongly inhibited from normal Diels–Alder reaction; B can react readily when its terminal substituent geometry permits the reactive s-cis arrangement.
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CoversDiels–Alder reactions-cis conformationsteric hindrancedi-tert-butylbutadienediene reactivity
All parts of Question 3
- 3(a)(i) Amination of 2-chloropyridine5 marks
- 3(a)(ii) Amination through 3,4-pyridyne10 marks
- 3(b) Steric control of Diels–Alder reactivity5 marks
- 3(c) Cinnamaldoxime rearrangement and ring closure10 marks
- 3(d) Aromatic character of diazines5 marks
- 3(e) Stability of three carbanions5 marks