Categories: C=O Bond Formation > Synthesis of Ketones
Synthesis of α-keto carboxylic acids, esters and amides
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Recent Literature
A chemoselective oxidation of α-hydroxy acids to α-keto acids is catalyzed by
2-azaadamantane N-oxyl (AZADO), a nitroxyl radical catalyst. The use of
molecular oxygen as a cooxidant enables the desired chemoselective oxidation to
α-keto acids, that are labile and can easily release CO2 under
oxidation conditions.
K. Furukawa, H. Inada, M. Shibuya, Y. Yamamoto, Org. Lett.,
2016, 18, 4230-4233.
Natural sunlight and air enable an efficient oxidation of α-aryl halogen
derivatives to the corresponding α-aryl carbonyl compounds at room temperature
through the combination of photocatalysis and organocatalysis. A plausible
mechanism was proposed on the basis of the mechanistic studies.
Y. Su, L. Zhang, N. Jiao, Org. Lett., 2011,
13, 2168-2171.
The reaction of aryl diazoacetates with H2O and diethyl
azodicarboxylate (DEAD) catalyzed by dirhodium acetate gives aryl α-keto esters
in high yields.
Z. Guo, H. Huang, Q. Fu, W. Hu, Synlett, 2006,
2486-2488.
An efficient intermolecular interception of alkyl azides by diazo(aryl)acetates
in the presence of dirhodium tetraoctanoate gives unstable α-imino esters
without overaddition of carbenoids to the C-N double bonds. After acidic workup,
the corresponding α-keto esters were obtained in very good yields.
P. Gu, X.-P. Wu, Y. Su, X.-Q. Li, P. Xue, R. Li, Synlett, 2014, 25,
535-538.
A recyclable, bifunctional iron nanocomposite catalyzes an efficient synthesis
of α-keto acids via oxidation of alkenes using TBHP as oxidant. A variety of
alkenes with different functional groups were smoothly oxidized into their
corresponding α-keto acids in good yields.
T. Song, Z. Ma, X. Wang, Y. Yang, Org. Lett., 2021, 23,
5917-5921.
A copper-catalyzed one-pot strategy for the synthesis of α-ketoamides from
1-arylethanols is highly efficient and delivers product in very good yields via
alcohol oxidation, sp3 C-H oxidation, and oxidative amidation.
N. Sharma, S. S. Kotha, N. Lahiri, G. Sekar, Synthesis, 2015, 47,
726-736.
A metal- and photocatalyst-free room-temperature amidation of amines with
feedstock phenacyl bromides provides α-ketoamides using molecular oxygen as an
oxidant as well as a source of oxygen. This visible light mediated and
base-promoted reaction offers good functional group tolerance (benzylic alcohol,
keto, cyano, nitro, halo, etc.), a broad substrate scope, and gram-scale
synthesis.
S. Das, S. Mondal, S. P. Midya, S. Mondal, E. Ghosh, P. Ghosh, J. Org. Chem., 2023, 88,
14847-14859.
A Cu-catalyzed oxidative amidation-diketonization reaction of terminal alkynes
leads to α-ketoamides. In this copper-catalyzed radical process, O2
not only participates as the ideal oxidant but also undergoes dioxygen
activation under ambient conditions.
C. Zhang, N. Jiao, J. Am. Chem. Soc., 2010,
132, 28-29.
Benzylimidates can directly be converted to primary α-ketoamides by using
molecular oxygen as an oxidant in the presence of copper(II) salt. The reaction
offers a wide substrate scope and operationally mild conditions.
Y. Kumar, M. Shaw, R. Thakur, A. Kumar, J. Org. Chem.,
2016, 81, 6617-6625.
A simple and efficient oxidative coupling of diazoesters and α-diazoketones
with NH4I provides primary oxamates and α-ketoamides in good yields. This metal-free protocol is performed
under mild conditions and has a wide substrate scope.
H. Wang, Y. Zhao, Y. Zheng, S. Fang, J. Li, X. Wan, J. Org. Chem., 2020, 85,
3050-3058.
The use of pyridine-N-oxides as oxidants under molecular iodine catalysis
enables a rapid, metal-free dioxygenation of ynamides. Furthermore, this
protocol could be extended to nonactivated alkynes, such as diarylacetylenes, to
provide various benzil derivatives.
S. W. Kim, T.-W. Um, S. Shin, J. Org. Chem., 2018, 83,
4703-4711.
2,3-Dichloropyridine N-oxide as oxygen transfer reagent enables gold(I)-catalyzed oxidation of alkynes to 1,2-dicarbonyls in
the absence of any acid additives and under mild conditions. The
developed strategy is also effective for ynamides, alkynyl ethers/thioethers,
and substrates bearing highly acid-sensitive groups. A one-pot
heterocyclization provides six-membered azaheterocycles.
A. Yu. Dubovtsev, N. V. Shcherbakov, D. V. Dar'in, V. Yu.
Kukushkin, J. Org. Chem., 2020, 85,
745-757.
An amination reaction of in situ generated gem-difluoro-enolates with
nitrosoarenes furnished α-ketoamides in very high yields. This nitroso aldol
reaction is very fast (typically completed within 5 min) and scalable and
tolerates various sensitive functional groups. Amination with azodicarboxylates
smoothly produced fluorinated α-amino ketones.
M. K. Reddy, I. Ramakrishna, M. Baidya, Org. Lett.,
2018, 20, 4579-4583.
A conjugate addition of ethyl cyanoacetates to chalcones and subsequent
iodine-promoted aerobic oxidation provides various α,δ-dicarbonyl esters. The
present protocol features mild reaction conditions, high efficiency, easily
available starting materials, and broad substrate scope.
H. Xu, M.-Y. Weng, H. Chen, Z. Zhang, Synthesis, 2020, 52,
1841-1846.
Related
The cross-coupling reaction of α-oxo acid chlorides with carbamoylsilanes
provides vicinal tricarbonyl amides in good yields under mild conditions. The
reaction of carbamoylsilanes with oxalyl chloride is accompanied by
decarbonylation to give vicinal tricarbonyl amides.
Y. Han, Y. Li, S. Han, P. Zhang, J. Chen, Synthesis, 2019, 51,
2977-2983.