Ring Expansion via Hydride Shift and Methyl Shift

Ring expansions occur as a carbocation rearrangement when an unstable cycloalkane is near a carbocation. You will come across ring expansion mechanisms during alkene reactions and later in SN1 and E1 reactions.

They key is to recognize when a ring is unstable, and the type of rearrangement that will help it become more stable. But don’t stop there. Ring expansions may be followed by a 1,2-hydride or 1,2-methyl shift.

The video below takes you through a tricky reaction mechanism taken from a students actual exam.

(Watch this video on YouTube or read the transcript coming soon)

Watch the previous video: Hydride Shift Methyl shift mechanism

Watch next video: Oxymercuration-Demercuration Reduction

Return to: Alkene Reaction Mechanisms Home Page

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  1. Hi Leah, does a hydride shift always take priority over a methyl/alkyl shift?

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