Which of the following correctly identifies the two possible enol tautomers that can be formed from $3-\mathrm{methyl}-2-\mathrm{butanone}$?

• A. $2-\mathrm{methyl}-3-\mathrm{buten}-2-\mathrm{ol}$ and $3-\mathrm{methyl}-2-\mathrm{buten}-1-\mathrm{ol}$
• B. $3-\mathrm{methyl}-2-\mathrm{buten}-1-\mathrm{ol}$ and $3-\mathrm{methyl}-1-\mathrm{buten}-2-\mathrm{ol}$
• C. $2-\mathrm{methyl}-2-\mathrm{buten}-3-\mathrm{ol}$ and $3-\mathrm{methyl}-2-\mathrm{buten}-2-\mathrm{ol}$
• D. $3-\mathrm{methyl}-2-\mathrm{buten}-2-\mathrm{ol}$ and $3-\mathrm{methyl}-1-\mathrm{buten}-2-\mathrm{ol}$

Answer: (D)

Verified step by step guidance

1. Identify the structure of 3-methyl-2-butanone, which is a ketone with a methyl group at carbon 3 and a carbonyl group at carbon 2 in a four-carbon chain.
2. Recall that enol tautomers form by the migration of an alpha hydrogen (a hydrogen on a carbon adjacent to the carbonyl) to the oxygen of the carbonyl group, creating a C=C double bond and an OH group.
3. Determine the alpha carbons adjacent to the carbonyl carbon (carbon 2). In 3-methyl-2-butanone, these are carbons 1 and 3, so enolization can occur at either position.
4. Draw the two possible enol forms: one with the double bond between carbons 2 and 3 and the OH on carbon 2 (3-methyl-2-buten-2-ol), and the other with the double bond between carbons 1 and 2 and the OH on carbon 1 (3-methyl-1-buten-2-ol).
5. Name these enol tautomers correctly by identifying the position of the double bond and the hydroxyl group, confirming that the two possible enols are 3-methyl-2-buten-2-ol and 3-methyl-1-buten-2-ol.