16. Conjugated Systems

Identify the type of the following pericyclic reaction.

Identify the type of following pericyclic reaction.

Given the following reaction: ${\mathrm{1,3}}_{\mathrm{butadiene}}$ reacts with $\mathrm{ethene}$ to form $\mathrm{cyclohexene}$, what is the correct classification of this pericyclic reaction?

Identify the type of pericyclic reaction shown below: $C_{6}H{6}_6$ undergoes a reaction with heat to form $C_{6}H{6}_6$ with a new six-membered ring. What is this reaction called?

Identify the type of following pericyclic reaction.