Reductive Synthesis of Nitrones from N-Hydroxyamides Using an Iridium Catalyst

Chida et al. have reported the reductive synthesis of nitrones from N-hydroxyamides using an iridium catalyst. According to their results, by using Vaska's catalyst [IrCl(CO)(PPh₃)₂] and 1,1,3,3-tetramethyldisiloxane, N-hydroxyamides are successfully transformed into the corresponding nitrones by two different types of reactions involving dehydrosilylations and hydrosilylations. This reaction shows high chemoselectivity even when various sensitive functional groups such as methyl esters are employed. Furthermore, it can be applied to the synthesis of macrocyclic nitrones, which are known to be difficult to synthesize by conventional methods. Since the obtained nitrones are promising key intermediates for the synthesis of biologically active compounds, this synthetic method has attracted considerable attention.