Which of the following ring formations must involve a suprafacial bond formation?

Question

Quizplus · Accepted Answer

Suprafacial bond formation involves the formation of bonds on the same face of a pi system. Four-membered rings, five-membered rings, and six-membered rings can all be formed through mechanisms that involve suprafacial interactions, such as those seen in pericyclic reactions (e.g., Diels-Alder reaction for six-membered rings, which is a [4+2] cycloaddition).

Which of the Following Ring Formations Must Involve a Suprafacial