Copper Compounds
Recent Literature
A simple and mild TEMPO-CuCl catalyzed aerobic oxidation of primary and
secondary alcohols in ionic liquid [bmim][PF6] gave the
corresponding aldehydes and ketones with no trace of overoxidation to carboxylic
acids. The product can be isolated by a simple extraction with organic solvent,
and the ionic liquid can be recycled or reused.
I. A. Ansari, R. Gree, Org. Lett., 2002, 4, 1507-1509.
A four-component system consisting of acetamido-TEMPO/Cu(ClO4)2/TMDP/DABCO
in DMSO allows an efficient room-temperature aerobic alcohol oxidation
of various alcohols into their corresponding aldehydes or ketones in
good to excellent yields. The catalytic system can be recycled.
N. Jiang, A. J. Ragauskas, J. Org. Chem., 2006, 71, 7087-7090.
A highly efficient and practical Pd(II)/Cu(OAc)2 catalyzed Saegusa
oxidation converts enol ethers to the corresponding enals at extremely low
catalyst loadings under ligand-free and aqueous conditions. Its synthetic
utility was demonstrated with a number of diverse substrates and large-scale
applications.
Q. Zhu, Y. Luo, Y. Guo, Y. Zhang, Y. Tao, J. Org. Chem., 2021, 86,
5463-5476.
The system Cu(ClO4)2/acetamido-TEMPO/DMAP catalyses
the room-temperature aerobic oxidation of primary alcohols to aldehydes in
the ionic liquid [bmpy]PF6. The catalysts can be recycled and
reused.
N. Jiang, A. J. Ragauskas, Org. Lett., 2005,
7, 3689-3692.
Ubiquitous carboxylic acids can serve as starting materials for a
photocatalytic decarboxylative C-O bond formation reaction that provides rapid
and facile access to the corresponding acetoxylated products.
S. Senaweera, K. C. Cartwrigt, J. A. Tunge, J. Org. Chem., 2019, 84,
12334-12343.
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 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.
A Chan-Lam coupling reaction of benzylic and allylic boronic esters
with primary and secondary anilines provides valuable alkyl amine products. Both
secondary and tertiary boronic esters can be used as coupling partners, with
mono-alkylation of the aniline occurring selectively.
J. D. Grayson, F. M. Dennis, C. C. Robertson, B. M. Partridge, J. Org. Chem., 2021, 86,
9883-9897.
A facile nickel-catalyzed oxidation of primary alcohols with
tetrabutylammonium peroxydisulfate in the presence of ammonium hydrogen
carbonate under basic aqueous conditions provides access to various aliphatic,
aromatic and heterocyclic nitriles in excellent yields with very high
purity.
F.-E. Chen, Y.-Y. Li, M. Xu, H.-Q. Jia, Synthesis, 2002, 1804-1806.
A general Pd-catalyzed oxidative aminocarbonylation of arylsilanes under mild
conditions is promoted by a commercially available copper(II) fluoride, which
acts as a dual silane activator and mild oxidant. The reaction is tolerant of a
wide range of arylsilanes and various sensitive halide functional groups as well
as a broad scope of amines.
J. Zhang, Y. Hou, Y. Ma, M. Szostak, J. Org. Chem., 2019, 84,
120-127.
A Mizoroki-Heck type reaction of boronic acids proceeds under a Pd(II)-mediated
pathway using a catalytic amount of Pd(OAc)2 in the presence of
Cu(OAc)2 as an oxidant. Treatment of a variety of alkenes with
boronic acids, boronates, and sodium tetraphenylborate furnishes β-arylated and
alkenylated products in very good yields.
X. Du, M. Suguro, K. Hirabayashi, A. Mori, T. Nishikata, N. Hagiwara, K. Kawata,
T. Okeda, H. F. Wang, K. Fugami, M. Kosugi, Org. Lett., 2001,
3, 3313-3313.
An arylation/alkenylation of homoenolates from cyclopropanol precursors with
boronic acids provides β-substituted enone and dienone derivatives in good
yields. A simple ligand-free Pd(II) catalytic system is most efficient under
open air conditions. The reaction tolerates a wide range of substrates and a
variety of functional groups.
T. Ramar, M. A. M. Subbaiah, A. Ilangovan, J. Org. Chem., 2022, 87,
4508-4523.
A chelated Pd(II)
complex catalyzes a coupling of organoborane reagents with cyclopropanol-derived β-ketone enolates
to provide synthetically important β-aryl ketone
intermediates in a chemoselective fashion.
T. Ramar, M. A. M. Subbaiah, A. Ilangovan, J. Org. Chem., 2020, 85,
7711-7727.
A carboxylic-acid-directed oxidative Heck reaction enables a direct synthesis
of 4-aryl-3-butenoic acids in good yields.
S. Yang, L. Liu, Z. Zhou, Z. Huang, Y. Zhao, Org. Lett., 2021, 23,
296-299.
An enantioselective alkoxycarbonylation-amination cascade process of terminal
allenes with CO, methanol, and arylamines proceeds under mild conditions (r.t.,
ambient pressure CO) via oxidative Pd(II) catalysis using a chiral aromatic
spiroketal-based diphosphine ligand and a Cu(II) salt as an oxidant to afford
various α-methylene-β-arylamino acid esters in good yields with excellent
enantioselectivity and high regioselectivity.
J. Liu, Z. Han, X. Wang, Z. Wang, K. Ding, J. Am. Chem. Soc., 2015,
137, 15346-15349.
A Rh(III)-catalyzed β-C(sp2)-H arylation of various acyclic
enamides with environmentally friendly arylsilanes offers extraordinary efficacy
and stereoselectivity, a wide scope of substrates, and good functional group
tolerance.
X. Jiang, G. Wang, Z. Zheng, X. Yu, Y. Hong, H. Xia, C. Yu, Org. Lett., 2021, 23,
31-36.
A palladium-catalyzed oxidative amination of inactive olefins with an
aromatic amine provides the corresponding
secondary and tertiary enamines in good yields using copper acetate as oxidant. This procedure enables an
efficient construction of enamine skeletons.
Q. Liu, Z. Zhou, Z. Huang, Y. Zhao, J. Org. Chem., 2023, 88,
15350-15357.
An oxidative cross-coupling reaction between activated olefins and vinyl
boronate provides synthetically useful (E,E)-1,3-dienes. Exclusive
stereoselectivity (only E,E-isomer) was achieved using base-free,
ligand-free, and mild catalytic conditions with [RuCl2(p-cymene)]2
as catalyst.
D. H. Dethe, N. C. Beeralingappa, A. Uike, J. Org. Chem., 2021, 86,
3444-3455.
Metal-catalyzed vinylic C-H activation enables a chemodivergent
cross-coupling of acrylamides and vinyl acetates. Depending on catalysts,
selective olefinic C-H vinylation and alkenylation reactions efficiently
generate a range of highly synthetically valuable butadienes with good
functional group tolerance in good yields.
R. Logeswaran, M. Jeganmohan, Org. Lett., 2021, 23,
5679-5683.
A low-barrier photoinduced ligand to metal charge transfer (LMCT) enables a
radical decarboxylative carbometalation strategy. Formation of a putative high-valent
arylcopper(III) complex facilitates reductive eliminations to
occur. This approach is suitable to address a previously unrealized general
decarboxylative fluorination of benzoic acids at low temperature.
P. Xu, P. López-Rojas, T. Ritter, J. Am. Chem. Soc.,
2021, 143, 5349-5354.
Ethyl bromodifluoroacetate as carbonyl source enables an efficient direct
carbonation of aromatic acids to yield monoalkyl phthalate derivatives in good
yields. A broad range of substrates bearing various functional groups were
tolerated.
N. Tao, J. Wang, C. Yuan, R. Zeng, Y.-S. Zhao,
Org. Lett., 2019, 21, 8607-8610.
A Pd(II)-catalyzed oxidative approach to construct polysubstituted pyrroles from
N-homoallylicamines and arylboronic acids proceeds through cascade
formation of C-C and C-N bonds via oxidative arylation of unactive alkenes,
followed by intramolecular aza-Wacker cyclization.
J. Zheng, L. Huang, C. Huang, W. Wu, H. Jiang, J. Org. Chem.,
2015,
80, 1235-1242.
A Pd-catalyzed annulation of enaminones and alkenes provides various NH-free
pyrroles via activation of multiple C(sp2)-H bonds. The evolution of
hydrogen has been confirmed by a hydrogen detector.
L. Fu, Y. Liu, J.-P. Wan, Org. Lett., 2021, 23,
4250-4255.
A Cu(OAc)2-promoted oxidation/[3+2]cycloaddition/aromatization
cascade reaction provides tetrasubstituted NH-pyrroles in very good
yields from a wide range of chalcones and diethyl iminodiacetates. This
convenient methodology has several advantages, such as the use of easily
accessible chalcones and readily available diethyl iminodiacetates, and mild
reaction conditions.
Z.-q. Lin, C.-d. Li, Z.-c. Zhou, S. Xue, J.-r. Gao, Q. Ye, Y.-j. Li, Synlett, 2019,
30,
1442-1446.
A novel palladium-catalyzed oxidative, intramolecular cyclocarbonylation
provides an efficient and direct approach for the construction of valuable
1,3,4-oxadiazole-2(3H)-ones and their derivatives.
F. Ji, X. Li, W. Guo, W. Wu, H. Jiang, J. Org. Chem.,
2015,
80, 5713-5718.
Whereas the reaction of O-homoallyl benzimidates with Cu(OAc)2
as oxidant involved an aza-Wacker-type intramolecular cyclization under
Pd-catalysis to deliver 4-methylene-1,3-oxazines, K2S2O8
as oxidant promotes a dimerization of O-homoallyl benzimidates to yield
benzohydrazonates (azines).
R. A. Fernandes, A. J. Gangani, Org. Lett.,
2022, 24, 7400-7404.
Cp*Co(CO)I2 catalyzes a weakly coordinating, carbonyl-assisted C-H activation of aromatic systems
with α,β-unsaturated ketone and subsequent aldol condensation to
provode indenes under mild reaction conditions. The reaction shows excellent functional group compatibility.
D. H. Dethe, N. C B, A. A. Bhat, J. Org. Chem., 2020, 85,
7565-7575.
A palladium-catalyzed C-H carbonylation of benzylamines provides
isoindolinone scaffolds in good yields under gas-free conditions by using
benzene-1,3,5-triyl triformate (TFBen) as a convenient CO surrogate.
L-Y. Fu, J. Ying, X. Qi, J.-B. Peng, X.-F. Wu, J. Org. Chem., 2019, 84,
1238-1246.
A facile synthesis of hydrazides from N-tosylhydrazones under
metal-free conditions was suitable for different substrates and tolerated
various substituents. In a subsequent step, a series of indazolones could be
prepared from corresponding o-bromobenzohydrazides under mild conditions.
S. Zhang, Q. Zhang, M. Tang, J. Org. Chem., 2022, 87,
3845-3850.
In a palladium-catalyzed oxidative carbonylation reaction for the synthesis of
phthalimides, an imine and H2O, which are generated in situ from the
condensation of aldehyde and amine, serve as self-sufficient directing group and
nucleophile, respectively. This method provides rapid access to phthalimides
starting from readily available materials with high atom- and step-economy in a
one-pot manner.
F. Ji, J. Li, X. Li, W. Guo, W. Wu, H. Jiang, J. Org. Chem.,
2018, 83, 104-112.
An unprecedented Pd(II)-catalyzed cascade annulation of o-aminobenzoic
acids with CO, amines, and aldehydes provides N3-substituted and N1,N3-disubstituted
2,3-dihydroquinazolin-4(1H)-ones in good yields under mild conditions. The
reaction offers low cost, high step economy, broad substrate scope, and good
product diversity.
X. Zhang, J. Wang, J. Xu, Q. Pang, D. Liu, G. Zhang, J. Org. Chem., 2023, 88,
10266-10276.
The use of Cu(OAc)2 enables a dehydrogenative cross-coupling between
two heteroarenes via disproportionation of the copper mediator. This synthetic
protocol provides a concise and "green" access to unsymmetrical biheteroarenes
bearing structural motifs of substantial utility in organic synthesis.
Z. F. Mao, Z. Wang, Z. Q. Xu, F. Huang, Z. K. Yu, R. Wang, Org. Lett., 2012,
14, 3854-3857.