Visible-light photocatalytic di- and hydro-carboxylation of unactivated alkenes with CO2

High value utilization of carbon dioxide (CO 2 ) has attracted worldwide attention for decades. Catalytic carboxylation of alkenes with CO 2 to synthesize valuable carboxylic acids and diacids is highly important. Although visible-light photocatalytic single-electron transfer reduction of CO 2 could provide an alternative choice for diverse chemo- and regio-selectivities, it has rarely been investigated in carboxylation. Moreover, visible-light photocatalytic carboxylation of unactivated alkenes with CO 2 •− has never been reported. Here we report visible-light photocatalytic di- and hydro-carboxylation of unactivated alkenes with CO 2 . In contrast to previous reports limited to activated alkenes, diverse unactivated aliphatic alkenes undergo selective carboxylations to give carboxylic acids, dicarboxylic acids and unnatural α-amino acid derivatives in moderate to good yields. Mechanistic studies suggest that CO 2 might be reduced to CO 2 •− via consecutive photo-induced electron transfer, and this species would attack unactivated alkenes followed by subsequent hydrogen atom transfer and other relevant processes to afford the corresponding products. The activation of CO 2 for catalytic carboxylation of alkenes is mainly limited to two-electron processes. Now, a visible-light photocatalytic single-electron transfer reduction of CO 2 is reported leading to the key intermediate CO 2 •− , which allows carboxylation of unactivated aliphatic alkenes.