Visible Light-induced Decarboxylative Alkylation of Heterocyclic Aromatics with Carboxylic Acids via Anthocyanin as a Photocatalyst.

: A visible light-induced decarboxylative alkylation of heterocyclic aromatics with aliphatic carboxylic acids was developed by using anthocyanins as photocatalyst under mild conditions. A series of alkylated heterocyclic compounds were obtained with in moderate to good yields by using the metal-free decarboxylative coupling reaction under blue light. This solving strategy used cheap and readily available carboxylic acids as alkylation reagents with good functional group tolerance and environmental friendliness. It is worth noting that this is the first time that anthocyanin have been used to catalyze the Minisci-type C-H alkylation. The mechanism of decarboxylation alkylation was studied by capturing adduct of alkyl radical and hydroquinone to confirmed the radical mechanism. This protocol also provided an alternative visible light-induced decarboxylative alkylation for the functionalization of heterocyclic aromatics.