# Why does furan undergo Diels Alder reaction?

Dec 27, 2016

Furan undergoes Diels-Alder reactions because it can behave as a dienophile.

#### Explanation:

Furan is classed as an aromatic compound because a lone pair on the oxygen can be delocalized into the ring to give a planar, cyclic, 6π conjugated system.

However, an $\text{O}$ atom is highly electronegative, so the delocalization is not overly effective.

The resonance stabilization of furan is only 67 kJ/mol compared to 150 kJ/mol for benzene.

The aromatic π system of furan can be disrupted if a process is energetically favourable.

Thus, furan readily undergoes Diels-Alder reactions and reacts as a diene in the presence of a dienophile.