A visible-light-catalyzed synthesis of 6-aryl substituted phenanthridines from aryl bromides and 2-isocyanobiphenyls at room temperature has been discovered. This metal-free cross-coupling reaction offers rapid and sustainable access to a series of structurally complex and diverse phenanthridines. The usage of inexpensive Rhodamine 6G as the catalyst with easy operation makes this protocol very practical.Download high-res image (205KB)Download full-size image

•Highly regioselective.•Metal-free, additive-free, and Br2-free.•“On water” and mild conditions.•Promising applications.A metal-, additive-, and Br2-free highly regioselective bromination of anilides using HBr and Selectfluor is presented. This reaction proceeded under mild conditions with high efficiency and good functional group tolerance, and water served as the solvent. In general, with substrates bearing no para-substituent, para-mono-bromination occurred exclusively, while ortho-mono-brominated anilides were the only products when para-positions were blocked. The incorporation of a stronger orienting group might result in a reversed regioselectivity, and the reaction was sensitive to steric hindrance.

A novel and simple strategy for the visible light-induced efficient synthesis of indol-3-yl aryl ketones from readily available arylsulfonyl chlorides and indoles with CO at room temperature was developed. This metal-free protocol has good functional group tolerance and avoids the use of transition-metal catalysts, additives, and alkaline or acidic reaction medium.

An efficient copper-catalyzed aerobic synthesis of bisaryl ketones from 1,2-diarylalkynes via C–C triple bonds cleavage has been demonstrated. The aniline compounds were found to be crucial in our conditions and a plausible mechanism was put forward. This reaction constitutes a new transformation from 1,2-diarylalkynes into bisaryl ketones with a practical, neutral, and mild synthetic approach.