Manganese(IV) oxide
Recent Literature
Manganese dioxide is employed as an in situ oxidant for the one-pot conversion
of alcohols into imines. In combination with polymer-supported cyanoborohydride
(PSCBH), a one-pot oxidation-imine formation-reduction sequence enables alcohols
to be converted directly into both secondary and tertiary amines.
L. Blackburn, R. J. K. Taylor, Org. Lett.,
2001, 3, 1637-1639.
A catalytic amount of manganese dioxide and solvent-free conditions under air
enabled a practical and efficient N-alkylation method for a variety of
sulfonamides and amines using alcohols as green alkylating reagents.
X. Yu, C. Liu, L. Jiang, Q. Xu, Org. Lett., 2011,
13, 6184-6187.
N-Heterocyclic carbenes catalyze the oxidation of unactivated aldehydes to
esters with manganese(IV) oxide in excellent yield under mild conditions. The reaction proceeds
through a transient activated alcohol generated in situ and
preserves stereochemical integrity. Various esters can be
synthesized using a broad range of alcohols and unactivated
aldehydes.
B. E. Marki, K. A. Scheidt, Org. Lett.,
2008,
10, 4331-4334.
N-Heterocyclic carbenes catalyze the oxidation of various allylic, propargylic,
and benzylic alcohols to esters with manganese(IV) oxide in excellent yields.
Saturated esters can also be accessed from aldehydes using this method. A
desymmetration of meso-1,2-diols using a chiral catalyst is described.
B. E. Maki, A. Chan, E. M. Phillips, K. A. Scheidt, Org. Lett., 2007,
9, 371-374.
A copper(II)-catalyzed intermolecular three-component oxyarylation of allenes
using arylboronic acids as a carbon source and TEMPO as an oxygen source
proceeded under mild conditions with high regio- and stereoselectivity and
functional group tolerance.
T. Itoh, Y. Shimizu, M. Kanai, Org. Lett., 2014,
16, 2736-2739.
Improved Dimethylsulfoxonium Methylide Cyclopropanation Procedures,
Including a Tandem Oxidation Variant
R. J. Paxton, R. J. K. Taylor, Synlett, 2007, 633-637.
A direct conversion of activated primary alcohols into terminal alkynes through
a sequential one-pot, two-step process involving oxidation with manganese
dioxide and then treatment with the Bestmann-Ohira reagent proceeds efficiently
under mild reaction conditions with a range of benzylic, heterocyclic and
propargylic alcohols.
E. Quesada, R. J. K. Taylor, Tetrahedron Lett., 2005,
46, 6473-6476.
Permanganate supported on active manganese dioxide can be used
effectively for the oxidation of arenes, alcohols and sulfides under
heterogeneous or solvent-free conditions.
A. Shaabania, P. Mirzaeia, S. Naderia, D. G. Leeb, Tetrahedron,
2004, 60, 11415-11420.
A. Shaabania, P. Mirzaeia, S. Naderia, D. G. Leeb, Tetrahedron,
2004, 60, 11415-11420.
A. Shaabania, P. Mirzaeia, S. Naderia, D. G. Leeb, Tetrahedron,
2004, 60, 11415-11420.
A method for the synthesis of N-aroylated sulfoximines involves a
manganese oxide promoted C-H activation of methyl arenes to form an aroyl
intermediate which then reacts readily with N-chlorosulfoximines to form
a series of valuable aroyl sulfoximine derivatives in high yields.
D. L. Priebbenow, C. Bolm, Org. Lett., 2014,
16, 1650-1652.
A copper-catalyzed intermolecular carboamination of potassium N-carbamoyl-β-aminoethyltrifluoroborates
with terminal, 1,2-disubstituted, and 1,1-disubstituted vinylarenes bearing a
number of functional groups provides 2-arylpyrrolidines. 1,3-Dienes are also
good substrates, and their reactions give 2-vinylpyrrolidines.
C. Um, S. R. Chemler, Org. Lett.,
2016, 18, 2515-2518.
The reaction of 1-aryl-2,2,2-trifluorodiazoethanes with alkenes provides
trifluoromethyl-substituted cyclopropanes with high diastereoselectivity and
enantioselectivity in the presence of an adamantylglycine-derived dirhodium
complex Rh2(R-PTAD)4 as catalyst.
J. R. Denton, D. Sukumaran, H. M. L. Davies, Org. Lett., 2007,
9, 2625-2628.
A step-economical access to polysubstituted aminoimidazoles via alkene vicinal
C-N bonds formation of 2-bromo-2-alkenones with guanidine avoids a NH-protection/derivatization
strategy. The reaction involves a tandem pathway of aza-Michael addition, SN2,
and a unique redox-neutral process and offers an excellent substrate scope.
S. K. Guchhait, N. Hura, A. P. Shah, J. Org. Chem.,
2017, 82, 2745-2752.
4-Substituted-1,4-dihydropyridines are readily and efficiently
aromatized in only one minute using commercial manganese dioxide in the
absence of an inorganic support at 100 °C under microwave irradiation.
This rapid procedure gives the dehydrogenated or 4-dealkylated product
in excellent yield.
M. C. Bagley, M. C. Lubinu,
Synthesis, 2006, 1283-1288.
