Metal-free oxidative C(sp³)–H functionalization: a facile route to quinoline formaldehydes from methyl-azaheteroarenes

Abstract

A facile protocol for the synthesis of quinoline formaldehydes via direct oxidative C–H bonds functionalization of methyl-azaheteroarenes in the presence of I2–DMSO has been described. This method is metal-free and easy to operate. This reaction provided a convenient route for the preparation of a range of important quinoline formaldehydes.

Recent advances in iodine–DMSO mediated C(sp3)–H functionalization of methyl-azaarenes via Kornblum oxidation

“…In the next year, Weng and coworkers also reported the synthesis of heteroaromatic aldehydes 51 from methyl azaarenes 20 in the presence of 1.5 equivalents of iodine and DMSO at 110 °C (eqn (2), Scheme 4). 27 Unlike the previous report, in this approach the heteroaromatic aldehydes can be afforded without any additives. Various electron donating and withdrawing groups on methyl azaarene were tolerated in the reaction system and 35–75% yields of the products were obtained.…”