Bingel reaction
The
Bingel reaction in
organic chemistry is a
fullerene cyclopropanation reaction to a
methanofullerene first discovered by C. Bingel in 1993 with the
bromo derivative of
diethyl malonate in the presence of a
base such as
sodium hydride or
DBU . The preferred double bonds for this reaction on the fullerene surface are the shorter bonds at the junctions of two hexagons (6-6 bonds) and the driving force is relief of
steric strain.
The reaction is of importance in the field of chemistry because it allows the introduction of useful extensions to the fullerene sphere. These extensions alter their properties for instance solubility and electrochemical behavior and therefore widen the range of potential technical applications.
The
reaction mechanism for this reaction is as follows: a
base abstracts the acidic malonate proton generating a
carbanion or
enolate which reacts with the electron deficient fullerene
double bond in a
nucleophilic addition. This in turn generates a carbanion which displaces bromine in a
nucleophilic aliphatic substitution in an
intramolecular ring
cyclopropane ring closure.
The Bingel reaction is a popular method in fullerene chemiistry. The
malonate (functionalized with the
halide atom) is often obtained
in situ in a mixture of
base and
tetrachloromethane or
iodine . The reaction is also known to take place with the
ester groups replaced by
alkyne groups in
dialkynylmethanofullerenes .
An alternative to the Bingel reaction is a fullerene
diazomethane reaction. N-(Diphenylmethylene)glycinate Esters in a Bingel reaction take a different conjugate course and react to a fullerene
dihydropyrrole.
 |
Bingel reaction with N-(Diphenylmethylene)glycinate Ester |
*
Fullerene chemistry @ Erlangen University* Complete understanding of the Bingel reaction required background knowledge in
organic chemistry# C. Bingel, Chem. Ber.
1993, 126, 1957.#
Structural Reassignment of the Mono- and Bis-Addition Products from the Addition Reactions of N-(Diphenylmethylene)glycinate Esters to [60]Fullerene under Bingel Conditions Graham E. Ball, Glenn A. Burley, Leila Chaker, Bill C. Hawkins, James R. Williams, Paul A. Keller, and Stephen G. Pyne J. Org. Chem.;
2005; 70(21) pp 8572 - 8574
DOI Graphical Abstract#
Synthesis of [60]Fullerene Adducts Bearing Carbazole Moieties by Bingel Reaction and Their Properties Yosuke Nakamura, Masato Suzuki, Yumi Imai, and Jun NishimuraOrg. Lett.;
2004; 6(16) pp 2797 - 2799;
DOI Graphical Abstract#
Covalent fullerene chemistry FranGois Diederich Pure &Appl. Chem., Vol. 69, No. 3, pp. 395-400,
1997 Online Article
