Safety of Hypervalent Iodine Reagents

02 April 2004

Simon Woodward from Nottingham University warns of the dangers of using reagents such as HIO₃-DMSO or I₂O₅-DMSO (Angew Chem Int Ed, 2003 , 42, 3981). Heating HIO₃ and DMSO at 80° on a 42 mmol scale resulted in an explosion after 30 min. The group of Nicolaou (Angew Chem Int Ed, 2002 , 41, 1386) had not had a problem with the reagents when they originally reported their use.

It is, however, well known that HIO₄ and DMSO will explode in concentrated solution (Rowe J J M, J Am Chem Soc, 1968 , 90, 1924). The most common hypervalent iodine reagents for oxidations are IBX and the Dess-Martin reagents. These are hazardous when scaled up (see Org Lett, 2002 , 4, 3001) so the best way to avoid problems is to use the stabilised form of IBX available from Simafex France (Org Lett, 2003, 15, 2903). For a useful review of this area of chemistry see Wirth T, (Top Current Chem, 2003, 224, 185).