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

High value utilization of carbon dioxide (CO2) has attracted worldwide attention for decades. Catalytic carboxylation of alkenes with CO2 to synthesize valuable carboxylic acids and diacids is highly important. Although visible-light photocatalytic single-electron transfer reduction of CO2 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 CO2•− has never been reported. Here we report visible-light photocatalytic di- and hydro-carboxylation of unactivated alkenes with CO2. 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 CO2 might be reduced to CO2•− 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.