A carbonyl compound P, which gives positive iodoform test, undergoes reaction with MeMgBr followed by dehydration to give an olefin Q. Ozonolysis of Q leads to a dicarbonyl compound R, which undergoes intramolecular aldol reaction to give predominantly S.
The structures of the products Q and R, respectively, are
(A)(see structure), (see structure)QR✓ Correct
(B)(see structure), (see structure)QR
(C)(see structure), (see structure)QR
(D)(see structure), (see structure)QR
Answer: (A)
Solution
Starting from compound P (identified in the previous question):
Reaction with MeMgBr adds a methyl group to the carbonyl
Dehydration forms the olefin Q
Ozonolysis of Q cleaves the double bond to give dicarbonyl R
Based on the structure of P and the reaction sequence, the correct structures for Q and R are shown in option (A).
JEE Advanced · 2009 · 12 Apr 2009 · Paper 1 · Single correct option
