Categories: C-O Bond Formation > Synthesis of esters >
Redox Esterification
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Name Reaction
Tishchenko Reaction
Recent Literature
Homoenolates are generated by reaction of N-heterocycle carbenes with enals,
leading to carbon-carbon bond formation or activated carboxylates depending
on the used base. The design of a new triazolium
precatalyst enabled the catalytic, atom-economical redox esterification of
enals.
S. S. Sohn, J. W. Bode, Org. Lett., 2005,
7, 3873-3876.
N-Heterocyclic carbenes are effective
catalysts for an Umpolung reaction of α,β-unsaturated aldehydes. The generated homoenolate species can be protonated, and the resulting activated
carbonyl unit is trapped with an alcohol nucleophile to form a saturated ester.
A. Chan, K. A. Scheidt, Org. Lett., 2005,
7, 905-908.
A cooperative catalyst system enhances both yield and selectivity of an
enantioselective N-heterocyclic carbene (NHC)-catalyzed β-protonation providing
a broad range of aryl-oxobutenoates and highly enantioenriched succinate
derivatives. The method demonstrates the benefits of combining different
activation modes in organocatalysis.
M. H. Wang, D. T. Cohen, C. Benjamin Schwamb, R. K. Mishra, K. A. Scheidt, J. Am. Chem. Soc., 2015,
137, 5891-5894.
A readily prepared, inexpensive thiolate-based catalyst enables a highly
selective, atom-economical crossed Tishchenko disproportionation of ortho-substituted
benzaldehydes with other aromatic aldehydes. The methodology is of exceptionally
wide scope and exhibits a high functional-group tolerance.
S. P. Curran, S. J. Connon, Angew. Chem. Int. Ed., 2012,
51, 10866-10870.
For Tishchenko reactions, selenide ions are superior catalysts to previously
reported thiolate analogues. These catalysts promote the disproportionation of
aldehydes with increased reaction rates and broader scope at lower catalyst
loadings and temperatures. Significantly improved catalyst performance was also
observed in the aryl selenide mediated crossed intermolecular Tishchenko
reaction.
S. P. Curran, S. J. Connon, Org. Lett., 2012,
14, 1074-1077.
The catalytic generation of activated carboxylates from epoxyaldehydes
enables a direct, anti-selective, convenient and mild synthesis of
β-hydroxyesters.
K. Y.-K. Chow, J. W. Bode, J. Am. Chem. Soc.,
2004,
126, 8126-8127.