PIFA-mediated intramolecular N -arylation of 2-aminoquinoxalines to afford indolo[2,3- b ]quinoxaline derivatives.

We present the PIFA-mediated intramolecular N -arylation of 2-aminoquinoxalines at room temperature for the first time. This method provides a wide range of indolo[2,3- b ]quinoxalines in good to excellent yields within a short time. The C-H bond functionalization occurs without the need for an inert atmosphere or additives. Additionally, a double C-H bond functionalization was observed, where the first reaction forms a C-N bond ( N -arylation) and the second forms a C-O bond, yielding an acetal-functionalized product. Mechanistic investigations suggest that the C-H bond functionalization proceeds through an ionic mechanism, whereas acetal functionalization follows a radical pathway. This method extends to the derivation of indoloquinoxalines, including the target compound BIQMCz.