Addition of Methyl Grignard and use of HClO4 in this question Okay so the first step is the use of Grignard. I know that Grignard does a 1,2 addition(generally) and the attack happens directly on the carbonyl,and I think HClO4 basically does protonation.Not sure about the role of NaOH. Also the final answer given is 3,5 dimethylphenol. The final product is devoid of the oxygen which is present in the ring. How should I approach this question?
Consider the resonance structures of the pyranone. MeMgCl attacks the structure shown second. The perchloric acid workup hydrolyses the enol ether to give the diketone shown bottom right. NaOH promotes the internal aldol cyclisation to give 3,5-dimethylphenol.