Question

Draw a stepwise mechanism for the following reaction. (Hint: Conjugate addition can occur with heteroatoms as well as carbon nucleophiles.)

Short answer

The addition reaction occurs when the conjugation is in the compound. The nucleophile attacks on the empty orbital of the double bond. The heteroatom nitrogen is more nucleophilic than the oxygen.

Therefore, the attack of hydroxyl amine occurs from the nitrogen end on the antibonding pi orbital.

Step-by-step solution

Addition reaction

The addition reaction occurs when the conjugation is in the compound. The nucleophile attacks on the empty orbital of the double bond. The heteroatom nitrogen is more nucleophilic than the oxygen.

Therefore, the attack of hydroxyl amine occurs from the nitrogen end on the antibonding pi orbital.

Explanation

In the first step, the hydroxyl amine attacks on the empty orbital of one of the double bonds.

In the second step, the intramolecular attack occurs from the hydroxyl amine to the empty orbital of the other double bond.

Nucleophilic attack