The oxidation methods using DMSO/I2 continue to grow. (For recent examples, see Synthesis Corner posts from January 6, 2020, October 31, 2019, and October 1, 2019.) These methods generally proceed through iodine-catalyzed C–H functionalization followed by a Kornblum-type oxidation at the same site. Along these lines, recent work by Chen et al. demonstrates the first example of a radical-free, metal-free oxidation of heteroaromatic methanes to produce heteroaromatic aldehydes using DMSO/I2.1
Under optimized conditions, the reaction of a variety of heteroaromatic methanes produced heteroaromatic aldehydes with good to excellent yields, regardless of the presence of electron-withdrawing or electron-donating groups or the ring position of the heteroatom (Table 1).