Oxygen
Name Reactions
Recent Literature
The combination of TEMPO and CAN can be used for the aerobic oxidation of
benzylic and allylic alcohols into their corresponding carbonyl compounds.
However, steric hindrance has been observed to impede the reaction with some
substituted allylic systems. The present method is superior to others
currently available due to its relatively short reaction times and excellent
yields.
S. S. Kim, H. C. Jung, Synthesis,
2003, 2135-2137.
A robust and effective Pd catalyst for the aerobic oxidation of various alcohols
has been discovered. Using a slightly higher concentration of acetic acid as
additive and extending the reaction times, the oxidation can be carried out
under ambient atmosphere of air.
D. R. Jensen, M. J. Schultz, J. A. Mueller, M. S. Sigman, Angew. Chem.
Int. Ed.,
2003, 42, 3810-3813.
Pd/C in aqueous alcohol with molecular oxygen, sodium borohydride,
and potassium carbonate efficiently oxidized benzylic and allylic alcohols.
Sodium borohydride allows a remarkable reactivation of active sites of the Pd
surface.
G. An, M. Lim, K.-S. Chun, H. Rhee, Synlett, 2007, 95-98.
A new, highly recoverable palladium-based catalyst for the aerobic oxidation
of alcohols combines an organic ligand and mesoporous channels that led to
enhanced activity, prevention of agglomeration and the generation of a
durable catalyst.
B. Karimi, S. Abedi, J. H. Clark, V. Budarin, Angew. Chem. Int. Ed., 2006,
45, 4776-4779.
Optimized selective aerobic oxidations in ionic liquids convert various
activated primary alcohols into their corresponding acids or aldehydes in good
to excellent yields. The newly developed catalytic systems could also be
recycled and reused for three runs without any significant loss of catalytic
activity.
N. Jiang, A. J. Ragauskas, J. Org. Chem.,
2007,
72, 7030-7033.
N. Jiang, A. J. Ragauskas, J. Org. Chem.,
2007,
72, 7030-7033.
Allylic alcohols were oxidized into aldehydes or ketones in the presence of
oxygen and Et3N using Pd(OAc)2 as catalyst. Diols with one
allylic function were selectively oxidized, with one of the hydroxyl groups
remaining untouched.
F. Batt, E. Bourcet, Y. Kassab, F. Fache, Synlett, 2007,
1869-1872.
Adsorbed [RuCl2(p-cymene)]2
on activated carbon is an efficient, environmentally attractive and highly
selective catalyst for use in aerobic oxidations, hydrolytic oxidations and
dehydrations. The heterogeneous catalyst was recovered quantitatively by simple
filtration and could be reused with minimal loss of activity.
E. Choi, C. Lee, Y. Na, S. Chang, Org. Lett., 2002, 4,
2369-2371.
An aerobic oxidation of primary and secondary alcohols to aldehydes and
ketones using TEMPO-CuCl as catalyst in the ionic liquid [bmin][PF6]
has been developed. The system needs no bubbling of O2 due to
its good solubility in the ionic liquid. The resulting aldehydes (with
no traces of carboxylic acids) and ketones can be extracted with organic
solvents. The ionic liquid can be reused after washing with water and
drying under high vacuum (8 runs for the oxidation of benzyl alcohol:
yields of 72%, 70, 68, 70, 65, 64, 62, and 60).
I. A. Ansari, R. Gree, Org. Lett., 2001, 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.
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.
1 mol-% TEMPO and a catalytic amount of 1,3-dibromo-5,5-dimethylhydantoin
and NaNO2 is a highly efficient catalytic system for the aerobic
oxidations of benzylic alcohols in water.
R. Liu, C. Dong, X. Liang, X. Wang, X. Hu, J. Org. Chem., 2005,
70, 239-244.
Oxidation of alcohols to aldehydes and ketones were performed under
atmospheric oxygen with a catalytic amount of V2O5
in toluene at 100°C. Secondary alcohols can be chemoselectively
converted into ketones in the presence of primary hydroxy groups.
S. Velusamy, T. Punniyamurthy, Org. Lett., 2004,
6, 217-219.
An efficient oxidation of various acetals, including open-chain acetals,
1,3-dioxanes and 1,3-dioxalanes, with molecular oxygen in the presence of
catalytic amounts of N-hydroxyphthalimide (NHPI) and Co(OAc)2
as co-catalyst gave esters.
B. Karimi, J. Rajabi, Synthesis,
2003, 2373-2377.
Oxidative ring expansion of methylenecyclopropanes with CAN under oxygen
atmosphere was investigated. A facile conversion affording
2,2-diarylcyclobutanones occurred in good yields.
V. Nair, T. D. Suja, K. Mohanan,
Synthesis, 2006, 2531-2534.
Several Pd-catalyzed oxidative cyclizations proceed in excellent yield under
simple aerobic conditions. Importantly, this system provided entry into
enatioselective catalysis with a readily available Pd-sparteine complex.
R. M. Trend, Y. K. Ramtohul, E. M. Ferreira, B. Stoltz,
Angew. Chem. Int. Ed., 2003, 42, 2892-2895.
A highly efficient carbon-carbon triple bond cleavage reaction of (Z)-enynols
offered a new route to highly substituted butenolides through a
gold(I)-catalyzed tandem cyclization/oxidative cleavage.
Y. Liu, F. Song, S. Guo, J. Am. Chem. Soc., 2006,
128, 11332-11333.
A set of benzimidazoles, 3H-imidazo[4,5-b]pyridines, purines, xanthines
and benzothiazoles was readily prepared from (hetero)aromatic ortho-diamines
or ortho-aminothiophenol and aldehydes using chlorotrimethylsilane in DMF
as a promoter and water-acceptor agent, followed by oxidation with air oxygen.
S. V. Ryabukhin, A. S. Plaskon, D. M. Volochnyuk, A. A. Tolmachev,
Synthesis, 2006, 3715-3726.
A highly efficient α alkylation of ketones with primary alcohols by the use
of a recyclable palladium catalyst has been demonstrated.
M. S. Kwon, N. Kim, S. H. Seo, I. S. Park, R. K. Cheedrala, J. Park,
Angew. Chem., 2005,
117, 7073-7075.
A general and mild protocol of oxygen-promoted Pd(II) catalysis allows a
selective cross-couplings of alkenyl- and arylboron compounds with various
olefins. Unlike most cross-coupling reactions, this new methodology works well
even in the absence of bases, consequently averting undesired homo-couplings.
K. S. Yoo, C. H. Yoon, J. W. Jung, J. Am. Chem. Soc., 2006,
128, 16348-16393.
A mild and efficient Pd(II) catalysis leads to the formation of carbon-carbon
bonds between various organoboron compounds and alkenes. The resultant Pd(0)
species is reoxidized by molecular oxygen to Pd(II). This protocol promotes the
desired Pd(II) catalysis, whereas the competing Pd(0) pathways (Heck or Suzuki)
are retarded.
Y. C. Jung, R. K. Mishra, C. H. Yoon, K. W. Jung, Org. Lett., 2003,
5, 2231-2234.
A facile and environmentally friendly synthetic method for a variety of
symmetrical 1,3-diyne derivatives is based on a Pd/C-CuI-catalyzed homocoupling
reaction of terminal alkynes. The reaction was efficiently catalyzed by an
extremely low loading of Pd/C and CuI in the presence of molecular oxygen as the
oxidant without any phosphine ligands and bases.
T. Kurita, M. Abe, T. Maegawa, Y. Monguchi, H. Sajiki, Synlett, 2007,
2521-2524.
A Pd-catalyzed Wacker-type oxidative cyclization under air allows the
construction of 2-methylquinolines in good yields under mild conditions.
Z. Zhang, J. Tang, Z. Wang, Org. Lett., 2008,
10, 173-175.
Ruthenium supported on alumina acts as an efficient heterogeneous catalyst for the oxidation of non-activated as well as activated amines to the corresponding nitriles or imines with 1 atm of dioxygen or air.
K. Yamaguchi, N. Mizuno, Angew. Chem. Int. Ed., 2003, 42, 1480-1483.
RuCl3-catalyzed oxidative cyanation of tertiary amines with sodium
cyanide under molecular oxygen at 60°C gives the corresponding α-aminonitriles
in excellent yields. This reaction is clean and should be an environmentally
benign and useful process.
S.-I. Murahashi, N. Komiya, H. Terai, T. Nakae, J. Am. Chem. Soc.,
2003,
125, 15312-15313.
A green dehydrogenation of hydrazo compounds using basic alumina or KF/alumina
under solvent-free conditions afforded azo compounds in good to excellent yields.
M. Mihara, T. Nakai, T. Iwai, T. Ito, T. Mizuno, Synlett, 2007,
2124-2126.
Oxidations of organic substrates such as sulfides, secondary amines, N-hydroxylamines,
and tertiary amines with molecular oxygen in the presence of
5-ethyl-3-methyllumiflavinium perchlorate catalyst and hydrazine monohydrate
in 2,2,2-trifluoroethanol occur highly efficiently to give the corresponding
oxidized compounds in excellent yields.
Y. Imada, H. Iida, S. Ono, S.-I. Murahashi, J. Am. Chem. Soc., 2003,
125, 2868-2869.
A regioselective one-pot synthesis of substituted pyrazoles from N-monosubstituted
hydrazones and nitroolefins gives products in good yields. A key
nitropyrazolidine intermediate is characterized and a plausible mechanism is
proposed.
X. Deng, N. S. Mani, Org. Lett.,
2006,
8, 3505-3508.
Two general protocols for the reaction of electron-deficient N-arylhydrazones
with nitroolefins allow a regioselective synthesis of 1,3,5-tri- and
1,3,4,5-tetrasubstituted pyrazoles. Studies on the stereochemistry of the key
pyrazolidine intermediate suggest a stepwise cycloaddition mechanism.
X. Deng, N. S. Mani, J. Org. Chem., 2008,
73, 2412-2415.
An asymmetric 1,2-addition of alkyl groups to conjugated cyclic enones
gave allylic alcohols with chiral quaternary centers. The resultant
allylic alcohols are converted into epoxy alcohols with excellent
diastereoselectivities. A semipinacol rearrangement provided α,α-dialkyl-β-hydroxy
ketones with all-carbon chiral quaternary centers.
S.-J. Jeon, P. J. Walsh, J. Am. Chem. Soc., 2003,
125, 9544-9545.
Highly enantio- and diastereoselective one-pot procedures for the synthesis
of epoxy alcohols involve either asymmetric addition of an alkylzinc reagent
to an enal or asymmetric vinylation of an aldehyde with divinylzinc
reagents. Exposure of the reaction mixtures to dioxygen and addition of
catalytic titanium tetraisopropoxide yields epoxy alcohols with good to
excellent yields.
A. E. Lurain, A. Maestri, A. R. Kelli, P. J. Carroll, P. J. Walsh, J. Am. Chem. Soc.,
2004,
126, 13608-13609.
A. E. Lurain, A. Maestri, A. R. Kelli, P. J. Carroll, P. J. Walsh, J. Am. Chem. Soc.,
2004,
126, 13608-13609.
The oxidation of substituted toluenes by molecular oxygen to the
corresponding substituted benzoic acids using Co(C18H35O2)2/NH4Br
or Co(OAc)2/NaBr/AcOH as catalysts in the presence of a
radical initiator in non-acidic solvents was investigated.
F. Yang, J. Sun, R. Zheng, W. Qiu, J. Tang, M. He, Tetrahedron,
2004, 60, 1225-1228.
A methyl group at an aromatic nucleus is oxidized directly to the
corresponding carboxylic acid in the presence of molecular oxygen and catalytic
hydrobromic acid under photoirradiation.
S.-I. Hirashima, A. Itoh,
Synthesis, 2006, 1757-1759.
Arylations of electron-rich heteroatom-substituted olefins were performed
with electron-rich arylboronic acids via palladium(II) catalysis. This mild
protocol, which offers access to functionalized enamides, exploits oxygen gas
for reoxidation and a stable 1,10-phenanthroline bidentate ligand to promote the
palladium(II) regeneration and to control the regioselectivity.
M. M. S. Andappan, P. Nilsson, H. v. Schenck, M. Larhed, J. Org.
Chem., 2004,
69, 5212-5218.
The chemoselective ring opening of N-tosyl aziridines with aldehydes
catalyzed by an N-heterocyclic carbene gave carboxylates of 1,2-amino alcohols. A plausible mechanism for this reaction
is discussed.
Y.-K. Liu, R. Li, L. Yue, B.-J. Li, Y.-C. Chen, Y. Wu, L.-S. Ding, Org. Lett., 2006,
8, 1521-1524.
Y. Imada, H. Iida, S. Ono, S.-I. Murahashi, J. Am. Chem. Soc., 2003,
125, 2868-2869.
Unsymmetrical diorgano-monosulfides, selenides, and tellurides can be
synthesized by the coupling of dichalcogenides with aryl- or alkylboronic acids
using a copper catalyst in air. The present reaction takes advantage of both
organochalcogenide groups on the dichalcogenide.
N. Taniguchi, J. Org. Chem., 2007,
72, 1241-1245.
A regio and anti-selective copper-catalyzed 1,2-hydroxysulfenylation
of alkenes can be carried out by the use of disulfides and acetic acid.
Reoxidation of intermediate sulfides by oxygen enables the use of both
organosulfide groups of the disulfides.
N. Taniguchi, J. Org. Chem., 2006, 71, 7874-7876.
A mild, efficient, and general aromatization of Hantzsch 1,4-dihydropyridines
with oxygen was realized at room temperature with 5 mol % of
9-phenyl-10-methylacridinium perchlorate as photocatalyst, which could be easily
recovered and reused.
X. Fang, Y.-C. Liu, C. Li, J. Org. Chem., 2007,
72, 8608-8610.
In the presence of activated carbon, Hantzsch 1,4-dihydropyridines and
1,3,5-trisubstituted pyrazolines were aromatized with molecular oxygen to the
corresponding pyridines and pyrazoles in excellent yields.
N. Nakamichi, Y. Kawashita, M. Hayashi, Synthesis, 2004,
1015-1020.
N. Nakamichi, Y. Kawashita, M. Hayashi, Synthesis, 2004,
1015-1020.
Treatment of chlorobis(methyldiphenylsilyl)methyllithium with various Grignard reagents and CuCN·2LiCl afforded 1,1-disilylalkylcopper
species. Subsequent aerobic oxidation provided various acylsilanes in good yields.
The preparation of
1-cyano-1-silylalkylcopper species via consecutive double 1,2-migration of alkyl
and cyano groups is described.
J. Kondo, A. Inoue, Y. Ito, H. Shinokubo, K. Oshima, Tetrahedron, 2005,
61, 3361-3369.
