Woollins' reagent
# Woollins' reagent

Woollins' reagent is an organic compound containing phosphorus and selenium. Analogous to Lawesson's reagent, it is used mainly as a selenation reagent. It is named after John Derek Woollins.

## Preparation

Woollins' reagent is commercially available. It can also be conveniently prepared in the laboratory by heating a mixture of dichlorophenylphosphine and sodium selenide $(Na_2Se),$ (itself prepared from reacting elementary selenium with sodium in liquid ammonia). An alternative synthesis is the reaction of the pentamer $(PPh)_5$ (pentaphenylcyclopentaphosphine) with elemental selenium.

## Applications

The main use of Woollins' reagent is the selenation of carbonyl compounds. For instance, Woollins' reagent will convert a carbonyl into a selenocarbonyl. Additionally, Woollins' reagent has been used to selenonate carboxylic acids, alkenes, alkynes, and nitriles.

