Chemistry

Materials science

Carboxylation

Carboxylic acid

Optoelectronics

Photochemistry

Alkyl

Organic chemistry

Electron transfer

Catalysis

Carbon atom

Carbon dioxide

Photocatalysis

Combinatorial chemistry

Visible spectrum

Nature Catalysis

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.                                                                  The activation of CO2 for catalytic carboxylation of alkenes is mainly limited to two-electron processes. Now, a visible-light photocatalytic single-electron transfer reduction of CO2 is reported leading to the key intermediate CO2•−, which allows carboxylation of unactivated aliphatic alkenes.

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