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In this problem, I know that initially a positive charge is formed at the carbon bearing the hydroxyl group , yielding a secondary carbocation.

But, I can't go any further with that. What kind of ring expansion could this be ?

How would we end up with 2 fused rings of different sizes and why? Is there any alkyl shift or hydride shift preceding the ring expanison?

I don't know how to predict the direction in which the expansion proceeds after the first step.

Can someone pls help me out with this? Thanks in Advance.


1 Answer 1


Answer should be 1.

Refer to the picture below, this may help you:

reaction mechanism


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