periodinane

Periodinanes are hypervalent iodine compounds derived from 2-iodobenzoic acid that serve as mild, selective oxidants in organic synthesis. The term commonly refers to iodine(V) reagents such as 2-iodoxybenzoic acid (IBX) and Dess-Martin periodinane (DMP), as well as related derivatives. These reagents feature iodine in high oxidation states bound to adjacent oxygen and aryl groups, allowing transfer of an oxygen atom to substrates in a single step.

IBX is relatively inexpensive but poorly soluble, often used in DMSO or DMF. Dess-Martin periodinane is a stabilized, more soluble derivative prepared by acetylation or similar modification of IBX; it is widely used for the oxidation of primary alcohols to aldehydes and secondary alcohols to ketones under mild conditions, typically at room temperature in dichloromethane or acetonitrile. DMP offers high chemoselectivity and tolerates many functional groups, with less overoxidation than some alternatives.

Mechanistically, periodinanes act as electrophilic oxygen-transfer reagents. The substrate's alcohol forms an alkoxy-iodinane intermediate, which collapses to the carbonyl product with concomitant reduction of iodine(V) to an iodobenzoic byproduct.

In practice, these reagents enable rapid, high-yielding oxidations without strong acids or bases. Limitations include cost, air- and moisture-sensitivity, and occasional incompatibility with highly oxidizable or sensitive substrates. Periodinanes remain valued for their mildness, operational simplicity, and compatibility with complex molecules. They are strong oxidants and should be handled with standard safety precautions to avoid moisture exposure and potential hazards.