Question

In the above reaction. Left hand side and right hand side rings are named as 'A' and 'B' respectively. They undergo ring expansion. The correct statement for this process is:

• A. Finally both rings will become six membered each.
• B. Finally both rings will become five membered each.
• C. Ring expansion can go upto seven membered rings
• D. Only 'A' will become 6 membered.

Answer 1

The Correct Option is A

In ring expansion reactions, smaller rings typically convert to larger rings to achieve greater stability and reduce ring strain. When both rings 'A' and 'B' undergo ring expansion, they both increase in size. The most common and stable outcome of such expansions is the formation of six-membered rings, which are energetically favorable due to their optimal bond angles and minimal ring strain. Therefore, both rings 'A' and 'B' will become six-membered rings after the expansion process.