Q3(b)(iii). Methoxy methyl benzoquinone with butadiene
Write the structure of the major product formed in the following reaction (100 °C): [2-methoxy-5-methyl-1,4-benzoquinone + buta-1,3-diene; structures given in the paper]
Answer in brief
Major product: the cis-fused Diels–Alder adduct formed at the methyl-bearing C=C of the quinone.
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CoversDiels–Alder reaction[4 + 2] cycloadditionbenzoquinonebutadieneregioselectivitycis ring fusion
All parts of Question 3
- 3(a)(i) Methyl cyanide heated with dilute HCl10 marks
- 3(a)(ii) Bromine addition to cis- and trans-2-butene5 marks
- 3(b)(i) Enone from a methoxy triene5 marks
- 3(b)(ii) Classify the rearrangement at 33 °C5 marks
- 3(b)(iii) Methoxy methyl benzoquinone with butadiene5 marks
- 3(c)(i) Acyl chloride to isocyanate; singlet and triplet nitrene10 marks
- 3(c)(ii) Indole at C-3; inertness of chlorobenzene10 marks