Categories: C-N Bond Formation > Synthesis of amides >
Oxidative amidations
Recent Literature
The combination of copper(I) iodide and an N-heterocyclic carbene catalyzes an
oxidative amidation of aldehydes with amines in the presence of tert-butyl
hydroperoxide. The method is simple and practicable, has a broad substrate
scope, and uses economical, feasible, and abundant reagents.
A. Singh, A. K. Narula, Synlett, 2021, 32,
718-722.
An operationally straightforward method for the amidation of aldehydes with
economic ammonium chloride or amine hydrochloride salts enables the synthesis of
various amides in good yield by using inexpensive copper sulfate or copper(I)
oxide as a catalyst and aqueous tert-butyl hydroperoxide as an oxidant.
Chiral amines can be used without detectable racemization.
S. C. Ghosh, J. S. Y. Ngiam, A. M. Seayad, D. T. Tuan, C. L. L. Chai, A. Chen, J. Org. Chem., 2012,
77, 8007-8015.
The use of diacetoxyiodobenzene in the presence of an ionic liquid enables a
facile one-pot synthesis of a series of amides from aldehydes and amines at
ambient temperature.
V. Prasad, R. R. Kale, B. B. Mishra, D. Kumar, V. K. Tiwari, Org. Lett., 2012,
14, 2936-2939.
A photoorganocatalytic reaction of aldehydes with diisopropyl azodicarboxylate
leads to an intermediate carbonyl imide, which can react with a variety of
amines to afford amides. This method enables a mild, one-pot, and
environmentally friendly synthesis of amides from aldehydes and amines.
G. N. Papadopoulos, C. G. Kokotos, J. Org. Chem.,
2016, 81, 7023-7028.
An oxidative amidation of aromatic aldehydes in the presence of low loadings of
phenazine ethosulfate as an inexpensive metal-free visible light photocatalyst
proceeds at ambient temperature and uses air as the sole oxidant. The
operationally easy procedure provides an economical, green, and mild alternative
for the formation of amide bonds.
D. Leow, Org. Lett.,
2014,
16, 5812-5815.
Using an efficient visible-light photocatalysis-based method, a mixture of an
aldehyde, tert-butyl hydrogen peroxide, and N-chlorosuccinimide
afforded an acid chloride in the presence of Ru(bpy)3Cl2
as photocatalyst. A subsequent reaction with an amine provided the corresponding
amide.
N. Iqbal, E. J. Cho, J. Org. Chem.,
2016,
81, 1905-1911.
In a fully catalytic nickel-photoredox process for the direct amidation of
aldehydes with nitroarenes, both substrates were photocatalytically activated
without the addition of an additional reductant or oxidant under mild
conditions. A preliminary mechanistic study indicates a reaction pathway in
which nitrobenzene is directly reduced to aniline as the nitrogen source.
J.-W. Sang, Q. Li, C. Zhang, Y. Zhang, J. Wang, W.-D. Zhang, Org. Lett., 2023, 25,
4592-4597.
A copper-catalyzed aerobic oxidative cross-dehydrogenative coupling (CDC) of
amines with α-carbonyl aldehydes leads to various α-ketoamides compounds. Many types of amines are
tolerant in this transformation. Wide
substrate scope, and the use of air as oxidant and initiator make this transformation
highly efficient and practical.
C. Zhang, X. Zong, L. Zhang, N. Jiao, Org. Lett., 2012,
14, 3280-3283.
The use of PhI=NTs/PhI=NNs as the nitrogen source in the presence of inexpensive iron(II) chloride + pyridine
as the in situ formed precatalyst enables amidation of aldehydes under mild conditions at room temperature or microwave assisted conditions.
The protocol is operationally straightforward and accomplished in good product yields and with complete chemoselectivity.
T. M. U. Ton, C. Tejo, S. Tania, J. W. W. Chang, P. W. H. Chan, J. Org. Chem., 2011,
76, 4894-4904.
A N-heterocyclic carbene catalyzes the oxidative esterification of various
aldehydes in the presence of 3,3',5'5-tetra-tert-butyldiphenoquinone to
yield hexafluoroisopropylesters, which are useful active esters for in situ
amide bond formation. This transition metal-free organocatalytic system also
enabled a mild oxidative azidation of aldehydes.
S. De Sarkar, A. Studer, Org. Lett., 2010,
12, 1992-1995.
A mild and efficient oxidative amidation of aldehydes uses amine HCl salts
and tert-butyl hydroperoxide as an oxidant in the presence of a
copper catalyst.
W.-J. Yoo, C.-J. Li, J. Am. Chem. Soc., 2006,
128, 13064-13065.
An iodine-NH3 • H2O system enables a direct transformation
of aryl, heteroaryl, vinyl, or ethynyl methyl ketones or carbinols to the
corresponding primary amides in good yields in aqueous media. A tandem
Lieben-Haller-Bauer reaction mechanism is proposed.
L. Cao, J. Ding, M. Gao, Z. Wang, J. Li, A. Wu, Org. Lett., 2009,
11, 3810-3813.
A metal-free oxidative-amidation strategy enables the synthesis of
α-ketothioamides and amides from α-azido ketones. The C-H bond thionation of
α-azido ketones with elemental sulfur could form α-ketothioacyl azide, which was
then nucleophilically attacked by amines, while amides could be formed with the
release of nitrogen gas and cyano anion in the presence of PhI(OAc)2.
P. Yu, Y. Wang, Z. Zeng, Y. Chen, J. Org. Chem., 2019, 84,
14883-14891.
A direct electrochemical amidation of α-ketoaldehydes and amines without
electrolytes at ambient temperature enables a catalyst- and oxidant-free
preparation of α-ketoamides with hydrogen as the sole byproduct. The reaction
offers clean and mild conditions, excellent functional-group tolerance, and high
atom economy and scalability.
J.-Y. Chen, H.-Y. Wu, Q.-W. Gui, X.-R. Han, Y. Wu, K. Du, Z. Cao, Y.-W. Lin,
W.-M. He,
Org. Lett., 2020, 22, 2206-2209.