The diol shown is first heated with dilute $H X_{2} SO X_{4}$ . The organic product is then treated with excess iodine in sodium hydroxide solution and the mixture is acidified. Which structure is the organic acid obtained?

AStructure A
BStructure B
CStructure C
DStructure D

Answer: B

Step 1: pinacol rearranges to pinacolone,

(CH X_{3}) X_{3} CCOCH X_{3}

. Step 2: the methyl ketone undergoes the haloform reaction, losing

CHI X_{3}

and leaving the carboxylate of the acyl part. Acidification gives 2,2-dimethylpropanoic (pivalic) acid; the tert-butyl group is untouched, so no carbon is lost from it.

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The diol shown is first heated with dilute HX2​SOX4​. The organic product is then treated with excess iodine in sodium hydroxide solution and the mixture is acidified. Which structure is the organic acid obtained?

Answer: B

More questions on Pinacol rearrangement products of drawn diols

The diol shown is first heated with dilute $H X_{2} SO X_{4}$ . The organic product is then treated with excess iodine in sodium hydroxide solution and the mixture is acidified. Which structure is the organic acid obtained?