The oxidant is a combination of dimethyl sulfoxide (DMSO) and dicyclohexylcarbodiimide (DCC).
The reaction was first reported by J. Moffatt and his student K. Pfitzner in 1963.
[1][2] The reaction requires one equivalent each of the diimide, which is the dehydrating agent, and the sulfoxide, the oxidant: Typically the sulfoxide and diimide are used in excess.
This species is highly reactive and is attacked by the alcohol.
Swern oxidations tend to give higher yields and simpler workup; however, they typically employ cryogenic conditions.