Categories: Synthesis of 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.
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.
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.
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.
