Photoarylation of Alkenes and Heteroaromatics by Dibromo-BINOLs in Aqueous Solution

Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes: Facile Synthesis of 1,2-[(Hetero)Aryl]n -o-Carboranes (n=1,2) and o-Carborane-Fused Cyclics

Photoarylation of iodocarboranes with unactivated arenes/heteroarenes at room temperature has been achieved, for the first time, thus leading to the facile synthesis of a large variety of cage carbon mono(hetero)arylated and di(hetero)arylated o-carboranes. This work represents a clean, efficient, transition-metal-free, and cheap synthesis of functionalized carboranes, which has significant advantages over the known methods.

Amine-catalyzed direct photoarylation of unactivated arenes

Constructing biaryls through direct aromatic C-H functionalization of unactivated arenes has become a popular topic in organic chemistry. Many efficient methods have been developed. In this Communication, a direct arylation of unactivated arenes with a broad range of aryl iodides is reported. This reaction proceeds through a new type of amine-catalyzed single electron transfer initiated radical coupling procedure to form biaryls in high yields under UV irradiation at room temperature. Only 20 mol% of TMEDA is used as the catalyst. No other additives are required for this transformation, thus avoiding the use of toxic transition metal catalysts, strong bases, or large amounts of other organic additives. This greener protocol provides a new strategy to achieve direct aromatic C-H functionalization and offers a new example of cost-effective and environmentally benign access to biaryls.