Alkene Carboxy-Alkylation via CO₂^•

Area of Science:

• Organic Chemistry
• Photocatalysis
• Green Chemistry

Background:

• Alkene functionalization remains a key challenge in organic synthesis.
• Developing efficient methods for carbon dioxide (CO2) utilization is crucial for sustainable chemistry.

Purpose of the Study:

• Introduce a new photocatalytic platform for alkene carboxy-alkylation.
• Exploit CO2 as a C1 building block for complex molecule synthesis.

Main Methods:

• Utilized a three-component reaction involving alkenes, carbonyl compounds, and formate as the CO2 precursor.
• Employed photocatalysis with *in situ* generated active photocatalyst from a precatalyst and DMSO.
• Investigated reaction mechanisms through mechanistic studies.

Main Results:

• Achieved efficient carboxy-alkylation of alkenes via CO2 radical anion (CO2•−) addition and radical polar crossover.
• Demonstrated the formation of diverse substituted γ-lactone products from vinylarenes and carbonyl compounds.
• Successfully synthesized medicinally relevant C(sp3)-rich heterocyclic scaffolds via dearomative carboxy-alkylation of indoles.

Conclusions:

• Developed a versatile and efficient photocatalytic system for alkene carboxy-alkylation.
• Formate serves as a practical CO2•− precursor, enabling the transformation of readily available starting materials.
• The methodology offers a sustainable route to valuable lactones and heterocyclic compounds.