Rongalite as a Methylene\nSurrogate: Synthesis of Heterodiarylmethanes <i>via</i> C(sp<sup>2</sup>)‑H Functionalization

An efficient method for the synthesis of heterodiarylmethanes\nthrough\nthe coupling of imidazo[1,2-<i>a</i>]pyridines and heteroarenes\nusing indoles employing rongalite as a methylenating reagent has been\ndeveloped. This regioselective C–H functionalization provides\na wide range of heterodiarylmethanes of imidazo[1,2-<i>a</i>]pyridines and imidazo[2,1-<i>b</i>]thiazole. Here, rongalite\nplays a crucial role in generating a C1 unit in situ, which triggers\nthe heterodiarylmethylation process. The use of inexpensive rongalite\n(ca. $0.03/1 g), mild reaction conditions, and gram-scale synthesis\nare some of the key features of this methodology.