[70]Fullerene-Fused Lactones: Regioselective Synthesis and Electrochemical Derivatization
Wen-Jie Qiu1, Zhiwei Xu1, Yu Liu2
1Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
Organic Letters
|March 23, 2026
Summary
Fullerene (C70)-fused lactones were synthesized using manganese(III) acetate or air promotion. Aerobic conditions yielded a single isomer, enabling regioselective functionalization for organic photovoltaics.
Area of Science:
- Organic Chemistry
- Materials Science
- Nanotechnology
Background:
- Fullerene derivatives are crucial in organic electronics.
- Controlling regioselectivity in fullerene functionalization remains a challenge.
Purpose of the Study:
- To synthesize novel fullerene (C70)-fused lactones.
- To investigate regioselective functionalization strategies for C70.
- To explore applications in organic photovoltaics.
Main Methods:
- Manganese(III) acetate-promoted synthesis of C70-fused lactones.
- Air-promoted regioselective synthesis of C70-fused lactone isomer 2a.
- Electrochemical generation of dianions for subsequent alkylation.
- Synthesis of C70-fused cyclobutanone (6a) using acyl chloride.
Main Results:
- Three isomers (2a-c) were obtained under Mn(OAc)3 conditions.
- Aerobic conditions selectively produced isomer 2a, a novel regioselective exohedral functionalization of C70.
- Alkylation of lactone 2a's dianion yielded monoalkylated (4a-c) and bisalkylated (5a-c) adducts.
- Unprecedented C70-fused cyclobutanone (6a) was synthesized.
- C70-fused cyclobutanone 6a achieved 19.0% power conversion efficiency in organic photovoltaics.
Conclusions:
- Regioselective synthesis of C70 derivatives is achievable under aerobic conditions.
- Novel C70-fused cyclobutanone shows promise for organic electronics.
- The developed methods offer pathways for advanced fullerene materials.
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