Categories: C=O Bond Formation > Synthesis of Ketones
Synthesis of 1,2-diketones
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Recent Literature
A highly efficient and mild procedure for the oxidation of different types of
alcohols uses TEMPO as catalyst, iodobenzene dichloride as stoichiometric
oxidant, and pyridine as base. Oxidation of 1,2-diols gives α-hydroxy ketones or
α-diketones depending on the amount of oxidant used. High yielding procedures
for the preparation of iodoarene dichlorides have been developed.
X.-F. Zhao, C. Zhang, Synthesis, 2007,
551-557.
Aerobic oxidation of deoxybenzoins is efficiently catalyzed by
1,4-diazabicyclo[2.2.2]octane (DABCO) with air as the sole oxidant to give the
corresponding benzils in excellent yields. The process has been successfully
extended to a one-pot synthesis of quinoxalines from benzyl ketones and aromatic
1,2-diamines.
C. Qi, H. Jiang, L. Huang, Z. Chen, H. Chen, Synthesis, 2011,
387-396.
A sequential dehydrogenation and transfer oxygenation of 1,2-diarylepoxides by
high-valent phenCu(III)(CF3)3 and DMSO provides
1,2-diketones. In situ generated CF3 radicals abstract the hydrogen
atom of the epoxide ring. The resulting ether α-carbon radical undergoes
ring-opening rearrangement to give a ketone α-carbon radical intermediate, which
is oxygenated by DMSO.
D.-D. Chen, S.-L. Zhang, J. Org. Chem., 2023, 88,
16735-16741.
A series of α-diketones were readily prepared by the nitroxyl-radical-catalyzed
oxidation of silyl enol ethers using magnesium monoperoxyphthalate hexahydrate (MMPP
• 6 H2O) as the co-oxidant.
M. Hayashi, M. Shibuya, Y. Iwabuchi, Synlett, 2012, 23,
1025-1030.
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.
A ruthenium-catalyzed oxidation of alkenes allows an efficient route to
α-diketones using TBHP as an oxidant, is highly functional group tolerant and
practically convenient, requires no additional ligand, and operates under mild
conditions with short reaction times. Based upon experimental observations, a
plausible mechanism is proposed.
S. Chen, Z. Liu, E. Shi, L. Chen, W. Wei, H. Li, Y. Cheng, X. Wan, Org. Lett., 2011,
13, 2274-2277.
A Wacker-type oxidation of alkynes catalyzed by PdBr2 and CuBr2
allows an efficient access to 1,2-diketones using molecular oxygen. Under
optimized conditions, various alkynes give 1,2-diketones in good yield. The
mechanism of this reaction was preliminarily investigated by control experiments.
W. Ren, Y. Xia, S.-J. Ji, Y. Zhang, X. Wan, J. Zhao, Org. Lett., 2009,
11, 1841-1844.
The combination of potassium persulfate and ambient air enables a catalyst- and transition-metal-free oxidation of various internal alkynes to the corresponding 1,2-diketones in very good yields.
Mechanistic studies indicate a radical process with both the persulfate salt and molecular
oxygen as source of the incorporated oxygen atoms.
D. Shen, H. Wang, Y. Zheng, X. Zhu, P. Gong, B. Wang, J. You. Y. Zhao, M. Chao, J. Org. Chem., 2021, 86,
5354-5361.
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.
The cheap and readily available organic dye eosin Y as photocatalyst enables the
oxidation of alkynes using air as the oxidant under metal-free conditions upon
irradiation with blue light to provide dicarbonylation products in good yields.
Some oxidation-sensitive groups, such as formyl and a carbon-carbon double bond,
were tolerated under the reaction conditions.
X. Liu, T. Cong, P. Liu, P. Sun, J. Org. Chem.,
2016, 81, 7256-7261.
A concerted metallophotoredox catalysis enables an efficient decarboxylative
functionalization of α,β-unsaturated carboxylic acids with aryl iodides in the
presence of perylene bisimide dye to afford 1,2-diketones.
S. Chand, A. K. Pandey, R. Singh, K. N. Singh, J. Org. Chem., 2021, 86,
6343-6350.
Benzil derivatives such as diaryl 1,2-diketones are synthesized via a direct
copper-catalyzed decarboxylative coupling reaction of aryl propiolic acids with
aryl iodides followed by an oxidation. The reaction shows good functional group
tolerance toward ester, aldehyde, cyano, and nitro groups. In addition,
symmetrical diaryl 1,2-diketones are obtained from aryl iodides and propiolic
acid in the presence of palladium and copper catalysts.
H. Min, T. Palani, K. Park, J. Hwang, S. Lee, J. Org. Chem., 2014,
79, 6279-6285.
The hypervalent iodine reagent PIDA in combination with a nucleophilic amine
(DABCO or pyridine) induces α-functionalization of enones via umpolung of
Morita-Baylis-Hillman type intermediates.
Depending on the presence of additional nucleophiles, α-chloro-enones, 1,2-diketones and α-tosyloxy-enones can be obtained.
S. Arava, S. K. Santra, G. K. Pathe, R. Kapanaiah, A. M. Szpilman, Angew. Chem. Int. Ed., 2000, 59,
15171-15175.
The combination of electrochemical and organoselenium-catalyzed processes
enables an unprecedented synthesis of α-keto acetals from readily available
terminal alkynes and alcohols. The desired products are obtained in a single
operation at room temperature in the absence of basic or metallic additives.
D. Ding, L. Xu, Y. Wei, J. Org. Chem., 2022, 87,
4912-4917.
A combination of copper powder and Selectfluor generates a cationic copper
species that efficiently catalyze the formation of 1,2-diketones from alkynes
under mild conditions with water and dioxygen as inexpensive and environmentally
benign sources of oxygen.
W. Zhang, J. Zhang, Y. Liu, Z. Xu, Synlett, 2013, 24,
2709-2714.
A low-temperature ozonolysis of alkynes enables a mild synthesis of
α-diketones.
J. L. Alterman, D. X. Vang, M. R. Stroud, L. J. Halverson, G. A. Kraus,
Org. Lett., 2020, 22, 7424-7426.
Oxidation of alkynes using ammonium persulfate and diphenyl diselenide as
catalyst in aqueous media leads to 1,2-unprotected dicarbonyl derivatives or to
hemiacetals starting from terminal alkynes.
S. Santoro, B. Battistelli, B. Gjoka, C.-w. S. Si, L. Testaferri, M. Tiecco, C.
Santi, Synlett, 2010,
1402-1406.
Oxidation of alkynes to α-dicarbonyl derivatives through a convenient
one-pot procedure via a Brønsted acid-promoted "hydration" and a DMSO-based
oxidation sequence has been achieved in high yields.
Z. Wan, C. D. Jones, D. Mitchell, J. Y. Pu, T. Y. Zhang, J. Org. Chem.,
2006, 71, 826-828.
The reaction of alkynes with N-iodosuccinimides and water at 70˚C allows
a convenient and practical approach to α-diketones.
M. Niu, H. Fu, Y. Jiang, Y. Zhao, Synthesis, 2008,
2879-2882.
1,3-Diols undergo smooth oxidative cleavage of the C-C bond in the presence of
2-iodoxybenzoic acid (IBX) affording 1,2-diketones in excellent yields under
mild conditions.
J. S. Yadav, S. K. Biswas, R. Srinivas,
Synthesis, 2006, 4237-4241.
An efficient and practical method enables the synthesis of unsymmetric benzils
from readily available β-ketoaldehydes via oxidation by sodium hypochlorite,
decarboxylation, and chlorination with Cl2 generated from sodium
hypochlorite. Various unsymmetric 1,2-diaryldiketones bearing functional groups
have been obtained in very good yields under mild reaction conditions.
L. Ruan, M. Shi, N. Li, X. Ding, F. Yang, J. Tang, Org. Lett., 2014,
16, 733-735.
A Selectfluor-mediated reaction of α,β-epoxy ketones provides 1,2-diketones in
good yields under transition-metal-free oxidative conditions via a ring-opening/benzoyl
rearrangement/C-C bond cleavage sequence.
H. Wang, S. Ren, J. Zhang, W. Zhang, Y. Liu, J. Org. Chem.,
2015,
80, 6856-6863.
Chalcone epoxides form α,α-dimethoxyacetophenones on heating with iodine in
methanol through C-C bond cleavage followed by acetalization of the formyl group.
The process occurs through ring opening of the chalcone epoxide by methanol to
form β-methoxy alcohol, cleavage of the C-C bond in the latter to form
α-ketoaldehyde, and acetalization of the formyl group to give the product.
B. G. Jadhav, S. D. Samant,
Synlett, 2014, 25, 1591-1595.
A direct metal-free α-hydroxylation of α-unsubstituted β-oxoesters and
β-oxoamides using m-chloroperbenzoic acid as the oxidant enables
straightforward metal-free access to important α-hydroxy-β-dicarbonyl moieties
under mild reaction conditions. Furthermore, the hydroxylated products can
readily be converted into vicinal tricarbonyl compounds, which are useful
synthetic precursors.
H. Asahara, N. Nishiwaki, J. Org. Chem.,
2014,
79, 11735-11739.
An aerobic decomposition of 1,3-diaryl-2-diazo-1,3-diketones to
1,2-diaryl-1,2-diketones (benzils) can be catalyzed by a few dirhodium
carboxylates (5 mol %) under a balloon pressure of oxygen at ambient
temperatures. An oxygen atom from O2 is shown to be incorporated into
the product accompanied by the extrusion of a carbonyl unit from the starting
materials.
J.-L. Zhu, Y.-T. Tsai, J. Org. Chem., 2021, 86,
813-828.
An efficient gold(I)-catalyzed oxidation of COR2-functionalized internal
alkynes provides α,β-diketoesters,
1,2,3-triketones, and α,β-diketoamides in good yields under
mild conditions in the presence of 2,6-dichloropyridine N-oxide. The utility of these compounds
was demonstrated by facile one-pot syntheses of azaheterocycles.
A. Y. Dubovtsev, D. V. Dar'in, V. Y. Kukushkin,
Org. Lett., 2019, 21, 4116-4119.