Categories: C-C Bond Formation > Oxygen-containing molecules > Carboxyl derivatives >
Synthesis of 1,4-keto carboxylic acids, esters and amides
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Recent Literature
Various oxo acid derivatives were obtained directly from the reaction of
aliphatic and aromatic aldehydes with ω-alkenoic acid derivatives in the
presence of rhodium(I) complexes and 2-amino-3-picoline.
E.-A. Jo, C.-H. Jun, Eur. J. Org. Chem., 2006, 2504-2507.
A photochemical process for the preparation of carboxylic acids from formate
salts and alkenes proceeds in high yields across diverse functionalized alkene
substrates with excellent regioselectivity. This operationally simple and
redox-neutral hydrocarboxylation can be readily scaled in batch at low
photocatalyst loading (0.01% photocatalyst).
S. N. Alektiar, Z. K. Wickens, J. Am. Chem. Soc.,
2021, 143, 13022-13028.
Visible-light photoredox-catalyzed fragmentation of methyl N-phthalimidoyl
oxalate allows direct construction of a 1,4-dicarbonyl structural motif by
a regioselective conjugate addition of the methoxycarbonyl radical to reactive
Michael acceptors.
Y. Slutskyy, L. E. Overman, Org. Lett.,
2016, 18, 2564-2567.
A simple light-driven three-component
aryl halide CO insertion, alkene insertion, and
protonation process,
utilizing Co2(CO)8 as an abundant solid carbonyl source,
provides 1,4-keto esters and 1,4-diketones in good
yields. The products can easily be subjected to further functionalization in
synthesis. Mechanism studies indicated that this reaction is initiated by the
generation of an aryl
radical.
Q. Mou, T. Han, M. Liu, Org. Lett., 2024,
26, 2169-2174.
An umpoled electrophilic 1,4-addition of CO2 to enones was achieved
under photocatalytic conditions in the presence of an iridium photocatalyst and
a benzimidazoline reductant under blue-light irradiation to give the
corresponding γ-keto carboxylic acids. Aldehydes also coupled with enones to
afford γ-keto alcohols (homoaldols) that were transformed into dihydrofurans and
tetrahydrofurans.
S. Okumura, K. Torii, Y. Uozumi, Org. Lett., 2023, 25,
5226-5230.
The decarboxylation of α-oxocarboxylic acids provides acyl radicals using a
readily accessible organic pyrimidopteridine photoredox catalyst under
ultraviolet-A (UV-A) light irradiation. These reactive acyl radicals smoothly
add to olefins and diverse Michael acceptors, with the assistance of H2O/D2O
as hydrogen donors, enabling easy access to a diverse range ketones, such as 2-oxocarboxylic
acids.
F. Gao, Z.-Y. Liao, Y.-Hang, Ye, Q.-H. Yu, C. Yang, Q.-Y. Luo, F. Du, B. Pan,
W.-W. Zong, W. Liang, J. Org. Chem., 2024, 89,
2741-2747.
In a photocatalytic methodology for a single step synthesis of γ-ketoacids
from α-ketoacids, maleic anhydrides are used as traceless synthetic equivalents
of acrylic acids. This selective cross-coupling is achieved via a dual
decarboxylative strategy, where CO2 is released as the only byproduct.
A highly regioselective, 3-component coupling with various alcohols provides
functionalized γ-ketoesters.
A. M. Davies, S. S. Londhe, E. R. Smith, J. A. Tunge, Org. Lett., 2023, 25,
8634-8639.
A Rh/(S,S)-DTBM-YanPhos complex catalyzes an asymmetric anti-Markovnikov hydroformylation of
α-substituted acrylates/acrylamides to provide a series of β-chiral linear aldehydes in high yields
and enantioselectivities.
S. Li, Z. Li, C. You, X. Li, J. Yang, H. Lv, X. Zhang,
Org. Lett., 2020, 22, 1108-1112.
Magnesium mediates a direct reductive carboxylation of easily prepared aryl
vinyl ketones to provide γ-keto carboxylic acids in good yields under an
atmosphere of carbon dioxide. The reaction offers eco-friendly reaction
conditions, a short reaction time and wide substrate scope and provided a useful
and convenient alternative to access biologically important γ-keto carboxylic
acids.
S. Zheng, T. Zhang, H. Maekawa, J. Org. Chem., 2022, 87,
7343-7349.
A cationic rhodium(I)/dppb complex catalyzed direct intermolecular
hydroacylation of N,N-dialkylacrylamides with both aliphatic and aromatic
aldehydes represents a versatile route to γ-ketoamides in view of high
atom economy and commercial availability of substrates.
K. Tanaka, Y. Shibata, T. Suda, Y. Hagiwara, M. Hirano, Org. Lett., 2007,
9, 1215-1218.
A cationic rhodium(I)/(R,R)-QuinoxP* complex catalyzes a highly
enantioselective direct intermolecular hydroacylation of α-substituted
acrylamides with unfunctionalized aliphatic aldehydes to yield the corresponding
γ-ketoamides in high yields with excellent ee values.
Y. Shibata, K. Tanaka, J. Am. Chem. Soc., 2009,
131, 12552-12553.
Iridium photoredox catalysis enables a decarboxylative 1,4-addition of 2-oxo-2-(hetero)arylacetic acids
to various Michael acceptors including α,β-unsaturated ester, ketone, amide, aldehyde, nitrile, and sulfone at room
temperature. 2-Oxo-2-(hetero)arylacetic acids are easily accessible precursors
of acyl anions through photoredox-catalyzed radical decarboxylation.
G.-Z. Wang, R. Shang, W.-M. Cheng, Y. Fu, Org. Lett., 2015,
17, 4830-4833.
Photoredox catalysis achieves a hydroacylation reaction of alkenes using readily
available carboxylic acids as the acyl source and hydrosilanes as a hydrogen
source. The protocol offers extremely mild conditions, broad substrate scope,
and good functional group tolerance.
M. Zhang, R. Ruzi, J. Xi, N. Li, Z. Wu, W. Li, S. Yu, C. Zhu, Org. Lett.,
2017, 19, 3430-3433.
Conjugated addition of primary nitroalkanes to α,β-unsaturated ketones or
α,β-unsaturated esters, in the presence of two equivalents of DBU, allows
the one-pot prepration of γ-diketones or γ-keto esters, respectively. The
reaction of 2-aryl-1-nitroethane derivatives with α,β-unsaturated ketones
gives cyclopentenones.
R. Ballini, L . Barboni, G. Bosica, D. Fiorini, Synthesis,
2002, 2725-2728.
The use of inexpensive and commercially abundant feedstock chemicals enables
a simple light-driven photocatalyst-free synthesis of β, δ-functionalized
ketones from aldehydes via direct acyl radical generation, hydrogen atom
transfer and a subsequent radical addition process. The method avoids the need
for prefunctionalized substrates and organometallic reagents.
Q. Mou, T. Han, M. Tian, M. Liu, J. Org. Chem., 2024, 89,
5189-5199.