Ring expansion reaction

From Wikipedia, the free encyclopedia

A ring expansion reaction is a type of organic reaction in which usually a hydrocarbon ring is expanded. Examples of ring expansions are:

• Beckmann rearrangement
• Dowd-Beckwith ring expansion reaction.

[edit] Ring contraction reaction

A ring contraction reaction is a type of organic reaction in which usually a hydrocarbon ring is contracted

Examples are:

• Favorskii rearrangement
• Demjanov rearrangement
• Ring contractions of cyclic ketones and cycloalkenes brought about by hypervalent iodine ^[1] for example the reaction of cyclohexene with iodosobenzene and boron trifluoride to cyclopentanecarbaldehyde:

[edit] References

1. ^ Hypervalent Iodine–Mediated Ring Contraction Reactions Luiz F. Silva, Jr Molecules 2006, 11, 421-434 Online article