Categories: Synthesis of N-Heterocycles >
Synthesis of 2-pyrrolines
Recent Literature
A chemoselective intramolecular hydroamination and hydroalkoxylation of
readily available α-allenic amines and alcohols provides valuable
2,3-dihydropyrroles and 2,3-dihydrofurans in the presence of low amounts of an
air and moisture stable iron catalyst. The mild reaction conditions allow fthe
hydrofunctionalization of a wide range of allenes bearing different functional
groups in good yields in the absence of base or any sensitive additives.
O. El-Sepelgy, A. Brzozowska, J. Sklyaruk, Y. K. Jang, V. Zubar, M. Rueping, Org. Lett.,
2018, 20, 696-699.
Ring-closing metathesis reactions of olefin-containing enamides using
ruthenium-based catalysts provides protected five- and six-membered cyclic
enamides.
S. S. Kinderman, J. H. van Maarseveen, H. E. Schoemaker, H. Hiemstra, F. P.
J. T. Rutjes,
Org. Lett., 2001, 3, 2077-2079.
An efficient, scalable and mild cyclocarboamination reaction of nonactivated
alkynes with aziridines, catalyzed by low loadings of Lewis or Bronsted acids,
provides a wide range of polysubstituted 2,3-dihydropyrroles in a highly
regioselective manner through a formal [3+2] cycloaddition.
P. A. Wender, D. Strand, J. Am. Chem. Soc., 2009,
131, 7528-7529.
By using [Rh(NBD)2]BF4 as the catalyst for intermolecular
cycloaddition of vinylaziridines with alkynes, a [3 + 2] cycloaddition reaction
was achieved with broad substrate scope and high stereoselectivity under mild
reaction conditions. When the catalyst was changed to [Rh(η6-C10H8)
(COD)]SbF6, the alternative [5 + 2] cycloadducts were selectively
formed under otherwise identical conditions.
J.-J. Feng, T.-Y. Lin, C.-Z. Zhu, H. Wang, H.-H. Wu, J. Zhang, J. Am. Chem. Soc., 2016,
138, 2178-2181.
A sequential reaction sequence for the synthesis of 5-aryl-2,3-dihydropyrroles,
starting from N-tosyl-protected 2-methylprop-2-en-1-amine, alkynyl
bromides, and arylboronic acids, involves nucleophilic addition of the
sulfonamide to the alkynyl bromide, followed by a palladium-catalyzed tandem
intramolecular Heck and intermolecular Suzuki cross-coupling reaction of the
bromoalkene adduct.
J. Peng, Y. Zhao, J. Zhou, Y. Ding, C. Chen, Synthesis, 2014, 46,
1881-1885.
A palladium-catalyzed intramolecular amination of alkenes with tosyl-protected
amines was achieved under mild reaction conditions in the presence of chloranil
to provide versatile dihydropyrrole derivatives with retention of olefin
functionalization in good yields.
B. Jiang, F.-F. Meng, Q.-J. Liang, Y.-H. Xu, T.-P. Loh, Org. Lett.,
2017, 19, 914-917.
A Brønsted acid catalyzed cyclization of aminodiazoesters with aldehydes
provides a wide range of 5 to 7-membered 3-carboxylate-N-heterocycles.
This reaction offers broad substrate scope and functional group compatibility.
Y. Jiao, A. Chen, B. Yu, H. Huang,
Org. Lett., 2020, 22, 6031-6034.
Ni(ClO4)2·6H2O can be used as a Lewis acid
catalyst for nucleophilic amine ring-opening cyclizations of donor-acceptor
(D-A) cyclopropanes to yield vinylogous 4-carboxy- and
4-keto-2,3-dihydropyrroles in good yields under milder reaction conditions than
previously reported. The reaction is amenable to a variety of D-A cyclopropanes
and primary amines.
M. C. Martin. D. V. Patil, S. France, J. Org. Chem., 2014,
79, 3030-3039.
Cascade reactions of saturated cyclic amines with 2-oxo-2-arylacetic acids
enable a highly regioselective and versatile synthesis of acylated N-heterocycles.
In this cascade process, the copper catalyst is believed to play a crucial role
not only in dehydrogenation but also in the decarboxylation and cross coupling
reaction.
X. Shi, X. Chen, M. Wang, X. Zhang, X. Fan, J. Org. Chem., 2018, 83,
6524-6533.
An intramolecular iminium ion cyclization reaction of readily accessible
Baylis-Hillman derivatives and aldehydes enables a synthesis of trans-4,5-disubstituted
3-carboxy-4,5-dihydropyrroles in good yield. These dihydropyrroles can easily be
converted to pyrroles or pyrrolidines.
J. Yiang, H. Xie, Z. Li, Q. Dang, X. Bai, Org. Lett.,
2015,
17, 3810-3813.
N-Sulfonyl-1,2,3-triazoles generate α-imino rhodium carbene complexes,
which further react with α,β-unsaturated aldehydes to produce trans-2,3-disubstituted
dihydropyrroles. The method can be successfully applied to a one-pot process
starting from terminal alkynes.
T. Miura, T. Tanaka, K. Hiraga, S. G. Stewart, M. Murakami, J. Am. Chem. Soc., 2013,
135, 13652-13655.
The combination of I2/PhI(OAc)2 promotes an
efficient and practical one-pot reaction of amines with alkyne esters and
chalcones under solvent-free ball-milling conditions to afford a variety of
polysubstituted trans-2,3-dihydropyrroles in good yields. This protocol
furnishes the corresponding pyrroles with the addition of DDQ as oxidant in a
subsequent step.
H. Xu, H.-W. Liu, K. Chen, G.-W. Wang, J. Org. Chem., 2018, 83,
6035-6049.