Categories: C-C Bond Formation > Oxygen-containing molecules > α,β-unsaturated compounds >
Synthesis of enones
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Recent Literature
Hydroacylation of alkynes is undoubtedly the simplest and most atom-efficient
approach for the synthesis of enones. A synergistic nickel-photocatalytic system
enables a highly regio- and stereoselective hydroacylation of unactivated
aldehydes and alkynes under mild conditions.
V. Murugesan, A. Muralidharan, G. V. Anantharajm, T. Chinnusamy, R. Rasappan, Org. Lett., 2022, 24,
8435-8440.
Highly regioselective vinylation of electron-rich olefins by halostyrenes is
effected by palladium catalysis with either mono- or bidentate phosphines in
DMSO as solvent. The use of hemilabile 1,3-bis(diphenylphosphino)propane
monoxide as a ligand led to faster reactions of more challenging 2-substituted
vinyl ethers and reduced Pd loadings.
M. McConville, O. Saidi, J. Blacker, J. Xiao, J. Org. Chem., 2009,
74, 2692-2698.
A new, efficient protocol for the highly stereoselective one-pot synthesis of (E)-styryl
ketones from styrenes is based on sequential ruthenium-catalyzed silylative
coupling-rhodium-catalyzed desilylative acylation reactions.
P. Pawluć, J. Szudkowska, G. Hreczycho, B. Marciniec, J. Org. Chem., 2011,
76, 6438-6441.
The use of MeCN:H2O as green solvent, Eosin Y as organic
photocatalyst, and ambient air as oxidant enables a metal-free, reliable
synthesis of α,β-unsaturated ketones from methyl arenes and aromatic alkynes.
This reaction offers high efficiency, use of green solvents, metal-free nature,
environmental friendliness, and visible light as a renewable energy source.
A. K. Kushwaha, A. Kamal, H. K. Singh, S. K. Maury, T. Mondal, S. Singh, Org. Lett., 2024,
26,
1416-1420.
Photoredox catalysis enables a domino-fluorination-protodefluorination
decarboxylative cross-coupling of α-keto acids with styrene to provide
α,β-unsaturated ketones under mild conditions.
M. Zhang, J. Xi, R. Ruzi, N. Li, Z. Wu, W. Li, C. Zhu, J. Org. Chem.,
2017, 82, 9305-9311.
A silver-catalyzed double-decarboxylative protocol enables an efficient and
pratical construction of chalcone derivatives via cascade coupling of
substituted α-keto acids with cinnamic acids under mild and environmentally
benign aqueous conditions.
N. Zhang, D. Yang, W. Wei, L. Yuan, F. Nie, L. Tian, H. Wang, J. Org. Chem.,
2015,
80, 3258-3263.
A Fe-mediated decarboxylative cross-coupling reaction between α-oxocarboxylic
acids and acrylic acids in aqueous solution provides an efficient and
expeditious approach to α,β-unsaturated carbonyl compounds. This transformation
offers a wide substrate scope and good functional group compatibility utilizing
inexpensive and easily accessible reagents. Mechanism studies suggest that a
free radical pathway is involved.
Q. Jiang, J. Jia, B. Xu, A. Zhao, C.-C. Guo, J. Org. Chem.,
2015,
80, 3586-3596.
A highly efficient, practical, and ligand-free palladium-catalyzed
carbonylation of aryl iodides with alkenylboronic acids provides a variety of
chalcones and α-branched enones in good yields under an ambient pressure of CO
at room temperature. Moreover, the transformation proceeds well in the presence
of a substoichiometric amount of base.
L. Tang, Y. Gao, J. Chen, L. Yang, B. Xiao, G. Shen, Y. Ouyang, W. Han, Synlett, 2023,
34,
1280-1284.
A CuI-catalyzed iodoformylation of terminal alkynes with TMSCF3
and NaI provides (E)-β-iodo-α,β-unsaturated aldehydes with excellent
chemoselectivity, regioselectivity, and stereoselectivity. This synthetic method
uses inexpensive and easy-to-handle chemical feedstocks. Synthetic applications
of the (E)-β-iodo-α,β-unsaturated aldehydes are
demonstrated.
D. Lu, X. Yang, W. Guan, S.-F. Yin, N. Kambe, R. Qiu, Org. Lett.,
2022, 24, 6993-6998.
A catalyzed formal hydroacylation of allenes with acid chlorides proceeds with
commercially available Pd(OAc)2 as catalyst and HSi(iPr)3
as reducing reagent to yield the corresponding α,β-unsaturated ketones regio-
and stereoselectively.
T. Fujihara, K. Tatsumi, J. Terao, Y. Tsuji, Org. Lett., 2013,
15, 2286-2289.
After treatment with bismesitylmagnesium, a range of tosylhydrazones furnishes
exceptionally high incorporation of the introduced electrophiles and good yields
of the functionalized styrenes. At conveniently accessible temperatures and with
a comparably small excess of base reagent and electrophile (for example 1.05
equiv of Weinreb amides), this modified Shapiro reaction offers an efficient
alternative to the lithium-mediated process.
W. J. Kerr, A. J. Morrison, M. Pazicky, T. Weber, Org. Lett., 2012,
14, 2250-2253.
Direct α-C-H acylation of various alkenes with aroyl fluorides using NHC,
sulfinate, and photoredox cooperative triple catalysis provides α-substituted
vinyl ketones in good yields with excellent functional group tolerance.
K. Liu, A. Studer, J. Am. Chem. Soc.,
2021, 143, 4903-4909.
In a method for the Friedel-Crafts-type insertion reaction of acetylene with
acid chlorides in chloroaluminate ionic liquids, the use of ionic liquids not
only serves to avoid the use of carbon tetrachloride or 1,2-dichloroethane but
also suppresses side reactions, and enables a simpler purification procedure,
giving a range of aromatic and aliphatic β-chlorovinyl ketones in high yield and
purity.
D. J. M. Snelders, P. J. Dyson, Org. Lett., 2011,
13, 4048-4051.
Iridium complexes show high catalytic activity in regio- and stereoselective
intermolecular additions of acid chlorides to terminal alkynes to afford
valuable (Z)-β-chloro-α,β-unsaturated ketones. Whereas a N-heterocyclic
carbene (NHC) is an efficient ligand for the addition of aroyl chlorides,
dicyclohexyl(2-methylphenyl)phosphine (PCy2(o-Tol)) enables
the reaction of aliphatic acid chlorides.
T. Miura, T. Biyajima, T. Fujii, M. Murakami, J. Am. Chem. Soc., 2012,
134, 194-196.
A copper-promoted reaction of 1-alkynes with α-carbonyl aldehydes in the
presence of morpholine enables an efficient and highly regio- and
stereoselective synthesis of E-1,2-dicarbonyl-3-ene derivatives.
S. Chen, Y. Li, H. Zhao, B. Li, J. Org. Chem., 2014,
79, 4137-4141.
1-Siloxy-1-alkenylcopper species were generated by 1,2-Csp2-to-O
silyl migration of the copper enolates of acyltriphenylsilanes. The
alkenylcopper species reacted with methyl, benzyl, allylic, tributylstannyl
halides and in the presence of Pd(0) catalyst with aryl and alkenyl iodides
to give geometrically pure (Z)-enol silyl ethers.
A. Tsubouchi, K. Onishi, T. Takeda, J. Am. Chem. Soc., 2006,
128, 14268-14269.
A 1,4-dipolar intermediate generated from pyridine and dimethyl
acetylenedicarboxylate reacted with aldehydes to give 2-benzoylfumarates via
the elimination of pyridine, whereas with N-tosylimines as
dipolarophiles the reaction afforded highly substituted 1-azadienes.
V. Nair, A. R. Sreekanth, N. Abhilash, A. T. Biju, B. R. Devi, R. S. Menon,
N. P. Rath, R. Srinivas, Synthesis,
2003, 1895-1902.
A photocatalytic strategy simultaneously addresses the construction of
trifluoromethylated quaternary carbon centers and the preparation of β-CF3-enones
through radical difunctionalization of α-CF3 alkenes with acyl
chlorides. This rapid assembly of structurally diverse fluorinated compounds
offers broad functional group compatibility, high efficiency, and atom economy.
Y. Zhou, Q. Jiang, Y. Cheng, M. Hu, X.-H. Duan, L. Liu, Org. Lett., 2024,
26, 2656-2661.
A nickel-catalyzed reductive coupling between vinyl triflates and acid
fluorides provides an efficient access to various enones. The reaction avoids
the use of acyl or vinyl metallic reagents, proceeds with a broad range of acid
fluorides and cyclic vinyl triflates, and tolerates several functional groups.
F.-F. Pan, P. Guo, C.-L. Li, P. Su, X.-Z. Shu,
Org. Lett., 2019, 21, 3701-3705.