Categories: Synthesis of N-Heterocycles > benzo-fused N-Heterocycles >
Synthesis of carbazoles
Name Reactions
Recent Literature
A palladium-catalyzed reaction sequence consisting of an intermolecular
amination and an intramolecular direct arylation enabled highly regioselective
syntheses of functionalized indoles or carbazoles and proved to be amenable to
the use of inexpensive 1,2-dichloroarenes as electrophiles.
L. Ackermann, A. Althammer, P. Mayer, Synthesis, 2009,
3493-3503.
The use of a magnetically recoverable palladium nanocatalyst supported on a
green biochar enables an efficient palladium-catalyzed tandem reaction for the
one-pot synthesis of 9H-carbazoles from inexpensive anilines and
1,2-dihaloarenes under microwave irradiation. The method shows a drastic
reduction in reaction times and excellent compatibility with different
functional groups.
H. S. Steingruber, P. Mendioroz, M. A. Volpe, D. C. Gerbino, Synthesis, 2021, 53,
2212-2218.
The iridium-catalyzed dehydrogenative cyclization of 2-aminobiphenyls proceeds
smoothly in the presence of a copper cocatalyst under air as a terminal oxidant
to yield N-H carbazoles. A similar catalytic system can also be used for a
dimerization reaction of 2-aminobiphenyl involving 2-fold C-H/N-H couplings.
C. Suzuki, K. Hirano, T. Satoh, M. Miura, Org. Lett.,
2015,
17, 1597-1600.
Various carbazoles can be synthesized from substituted biaryl azides at 60°C
using Rh2(OCOC3F7)4 or Rh2(OCOC7H15)4
as catalysts.
B. J. Stokes, B. Jovanović, H. Dong, K. J. Richert, R. D. Riell, T. G. Driver, J. Org. Chem., 2009,
74, 3225-3228.
Double Cu-catalyzed C-N coupling reactions of 2,2′-dibromobiphenyl and amines
enable an efficient synthesis of carbazole derivatives in the presence of
air. The reaction is robust, proceeds in high yields, and tolerates a series of
amines including neutral, electron-rich, electron-deficient aromatic amines and
aliphatic amines.
H. N. Do, N. M. Quan, B. V. Phuc, D. V. Tinh, N. Q. Tien, T. T. T. Nga, V. T.
Nguyen, T. Q. Hung, T. T. Dang, P. Langer, J. An, Synlett, 2021,
32,
611-615.
Trivalent Organostibines: Sb,N Ligands in Double N-Arylation of Primary
Amines toward Functionalized Carbazoles
L. Peng, Y. Zhao, J. Chen, H. Lu, Z. Tang, Y. Chen, S.-F. Yin, N. Kambe, R.
Qiu, J. Org. Chem., 2024, 89,
183-190.
A Pd(II)-catalyzed C-H bond amination reaction operates under extremely mild
conditions and produces carbazole products in good to excellent yields.
Carbazoles possessing complex molecular architecture can also be formed using
this reaction, highlighting its potential in natural product synthesis
applications.
J. A. Jordan-Hore, C. C. C. Johansson, M. Gulias, E. M. Beck, M. J. Gaunt, J. Am. Chem. Soc., 2008,
130, 16184-16186.
An intramolecular palladium(II)-catalyzed oxidative carbon-carbon bond formation
under air in the presence of pivalic acid as the reaction solvent, instead of
acetic acid, results in greater reproducibility, higher yields, and broader
substrate scope. The reaction allows the conversion of both electron-rich and
electron-deficient diarylamines.
B. Liégault, D. Lee, M. P. Huestis, D. R. Stuart, K. Fagnou, J. Org. Chem., 2008,
73, 5022-5028.
A palladium-catalyzed tandem directed C-H
functionalization and amide arylation gave a series of substituted carbazoles. The Pd(0) species
generated are reoxidized to Pd(II) in the presence of Cu(OAc)2 and an atmosphere
of oxygen.
W. C. P. Tsang, N. Zheng, S. L. Buchwald, J. Am. Chem. Soc.,
2005, 127, 14560-14561.
An efficient route to carbazoles and dibenzofurans has
been developed. The reaction of
o-iodoanilines or o-iodophenols with silylaryl triflates in the
presence of CsF to afford N- or O-arylated products is followed by
a cyclization using a Pd catalyst to carbazoles and dibenzofurans in good to
excellent yields. Various functional groups are tolerated.
Z. Liu, R. C. Larock, Org. Lett., 2004, 6, 3739-3741.
Ultrasmall nanoclusters offer a high surface area and unsaturated active
sites. A copper nanocluster-based catalyst enables C-N bond-forming reactions of
aryl chlorides under visible-light irradiation at room temperature. A range of
N-heterocyclic nucleophiles and electronically and sterically diverse
aryl/hetero chlorides react to provide C-N coupling products in good yields.
A Sagadevan, A. Ghosh, P. Maity, O. F. Mohammed, O. M. Bakr, M. Rueping, J. Am. Chem. Soc.,
2022, 144, 12052-12061.
NH4I promotes an efficient indole-to-carbazole strategy under
metal-free conditions. The reaction offers high regioselectivity through formal
[2 + 2 + 2] annulation of indoles, ketones, and nitroolefins and enables the
assembly of a large number of diversified carbazoles with good functional group
tolerance.
S. Chen, Y. Li, P. Ni, H. Huang, G.-J. Deng, Org. Lett.,
2016, 18, 5384-5387.
Either spirocyclic indolenines or carbazoles can be generated from a common
indole-tethered propargyl alcohol precursor in high yields upon treatment with
different Ag(I) catalysts at rt. An unexpected hydration reaction to afford (±)-actinopolymorphol
B is also reported.
M. J. James, R. E. Clubley, K. Y. Palate, T. J. Procter, A. C. Wyton, P.
O'Brien, R. J. K. Taylor, W. P. Unsworth, Org. Lett.,
2015,
17, 4372-4375.
A sequential cascade process for the synthesis of iodocarbazoles through a
tandem iodocyclization with migration and aromatization can be conducted at room
temperature and in a short time.
J. Wang, H.-T. Zhu, Y.-F. Qiu, Y. Niu, S. Chen, Y.-X. Li, X.-Y. Liu, X.-M. Liang, Org. Lett.,
2015,
17, 3186-3189.
AuCl3-catalyzed cyclizations of 1-(indol-2-yl)-3-alkyn-1-ols occurred
smoothly in toluene at room temperature leading to a series of carbazole
derivatives efficiently. A possible mechanism has been proposed.
Y. Qiu, W. Kong, C. Fu, S. Ma, Org. Lett., 2012,
14, 6198-6201.
A gold(I)-catalyzed intramolecular hydroarylation of (Z)-2-(enynyl)indoles
gives carbazoles in good yields. The requisite (Z)-2-(enynyl)indoles were
synthesized stereoselectively by trimethylgallium-promoted, Z-selective
Wittig olefination of N-alkylindole-2-carboxaldehydes with propargyl
ylides.
C. Praveen, P. T. Perumal, Synlett, 2011,
268-272.