Frozen aryldiazonium chlorides in radical reactions with alkenes and arenes

Frozen aryldiazonium chlorides have been investigated in radical alkene and arene functionalizations. Through freezing at – 84?°C, aryldiazonium chlorides, which otherwise show significant decomposition in aqueous solution after several hours at room temperature, can be stored for at least 20 days. In addition, the slow melting of aryldiazonium-containing ice cubes can serve as an alternative to syringe pumps that are commonly used if a controlled addition of the diazonium salt to the reaction mixture is required.