Photocatalyst‐Free Visible‐Light‐Promoted C‐3‐Alkylation of Indoles through C−H Functionalizations of N , N ‐Dialkylanilines

Abstract Visible‐light, an environmentally benign and sustainable energy source, is considered an ideal condition for green chemical synthesis especially through C−H functionalization which has been a major focus for the synthesis of organic molecules in the last two decades. Here, we report a visible‐light driven photocatalyst‐free C‐3‐alkylation of indoles via C−H functionalizations of N , N ‐dialkylanilines. When N,N ‐dialkylaniline is reacted with various substituted indoles in DMSO solvent in an open reaction vessel at room temperature (r.t.) under the irradiation of a Compact Fluorescent Light (CFL, 27 W), C‐3‐alkylation of indoles occurs. The yield of the resulting product is up to 96 %. This photochemical transformation offers several advantages such as catalyst‐free, aerial oxygen as the sole oxidant, visible‐light promoted, and tolerable for various functional groups in indoles.