Categories: C-C Bond Formation > Cyclic compounds > Cycloalkanes
Synthesis of cyclopentanes
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Name Reactions
Conia-Ene Reaction
Recent Literature
Reduction of stilbenes with Na metal in dry THF allowed easy access to various
1,2-diaryl-1,2-disodiumethanes. These diorganometallic intermediates gave
1,2-diarylethanes upon aqueous work up, or trans-1,2-diaryl-substituted
cyclopentanes by cycloalkylation with 1,3-dichloropropanes.
U. Azzena, G. Dettori, C. Lubinu, A. Mannu, L. Pisano, Tetrahedron,
2005, 61, 8663-8668.
Microscale parallel experimentation was used to discover catalyst systems
capable of coupling secondary organotrifluoroborates with aryl chlorides and
bromides. A ligand-dependent β-hydride elimination/reinsertion mechanism was
implicated in the cross-coupling of more hindered substrates, leading to
isomeric mixtures of coupled products in some cases.
S. D. Dreher, P. G. Dormer, D. L. Sandrock, G. A. Molander, J. Am. Chem. Soc., 2008,
130, 9257-9259.
A stannane, which is simple to prepare, was successfully used in standard
radical reactions as replacement of Bu3SnH and Ph3SnH. The
tin-containing byproducts are removed by mild hydrolysis and extraction with
aqueous NaHCO3. The performance of this new reagent was tested for
reactions involving halides, selenides, Barton-McCombie deoxygenation and enyne
cyclization.
D. L. J. Clive, J. Wang, J. Org. Chem., 2002, 67,
1192-1198.
N-heterocyclic carbenes catalyze intramolecular β-alkylations of
α,β-unsaturated esters, amides, and nitriles that bear pendant leaving groups to
form a variety of ring sizes. The mechanism is discussed.
C. Fischer, S. W. Smith, D. A. Powell, G. C. Fu, J. Am. Chem. Soc.,
2006, 128, 1472-1473.
A new methodology for the cycloisomerization of dienes using a Grubbs carbene
complex and trimethylsilyl vinyl ether has been established. The utility of this
reaction was demonstrated by in the synthesis of exo-methylene
heterocyclic compounds, which could act as key intermediates for
pharmacologically active compounds.
Y. Terada, M. Arisawa, A. Nishida, Angew. Chem. Int. Ed., 2004,
43,
4063-4067.
Cobalt complex/Zn systems effectively catalyze the reductive coupling of
activated alkenes with alkynes in the presence of water to give substituted
alkenes with very high regio- and stereoselectivity in excellent yields.
H.-T. Chang, T. T. Jayanth, C.-C. Wang, C.-H. Cheng, J. Am. Chem. Soc.,
2007,
129, 12032-12041.
InCl3 and (Cy)(i-Pr)NH efficiently promote the
carbocyclization reaction of α-disubstituted aldehydes to give functionalized
cyclopentanes in very good yields through a combination of enamine-type
catalysis with an indium-catalyzed activation of alkynes.
B. Montaignac, M. R. Vitale, V. Michelet, V. Ratovelomanana-Vidal, Org. Lett., 2010,
12, 2582-2585.
A novel alkenylative cyclization of enyne was developed using Cp*RuCl(cod) under
ethylene gas at room temperature.
M. Mori, N. Saito, D. Tanaka, M. Takimoto, Y. Sato, J. Am. Chem. Soc.,
2003, 125, 5606-5607.
Palladium-catalyzed inter- and intramolecular enyne coupling reactions were
developed. The reaction involves the acetoxypalladation of the alkyne, followed
by the insertion of the alkene and the protonolysis of the carbon-palladium bond.
The coupling allows the construction of synthetically important carbo- and
heterocycles.
L. Zhao, X. Lu, W. Xu, J. Org. Chem., 2005, 70, 4059-4063.
A Ni(II)-catalyzed Conia-ene reaction of various acetylenic 1,3-dicarbonyl
compounds has been discovered. The reaction gave mono- and bicyclic olefinic
cyclopentantes in good yields in the presence of Ni(acac)2 and
Yb(OTf)3.
Q. Gao, B.-F. Zheng, J.-H. Li, D. Yang, Org. Lett., 2005, 7,
2185-2188.
[ReBr(CO)3(thf)]2 catalyzed the reactions of
1,3-dicarbonyl compounds with terminal acetylenes, which gave the corresponding
alkenyl derivatives in excellent yields.
Y. Kuninobu, A. Kawata, K. Takai, Org. Lett., 2005, 7,
4823-4825.
An enantioselective Conia-ene reaction of acetylenic β-dicarbonyl compounds employs a
DTBMSegphos-Pd(II)/Yb(III) dual catalyst system that allows for the asymmetric
synthesis of all-carbon quaternary centers and generates a methylene
cyclopentane containing an
alkene that can be further manipulated.
B. K. Corkey, F. D. Toste, J. Am. Chem. Soc., 2005,
127, 17168-17169.
An intramolecular iodo-aldol cyclization of prochiral α-substituted enoate
aldehydes and ketones produces hetero- and carbocycles containing quaternary centers adjacent
to secondary or tertiary centers. The reactions occur in good yields and are
highly trans-selective with hydroxyl and iodomethyl
groups on opposite faces of the ring system.
F. Douelle, A. S. Capes, M. F. Greaney, Org. Lett., 2007,
9, 1931-1934.
A novel approach to 3(2H)-furanones combines a transition-metal-catalyzed
activation of alkynes with a heterocyclization and subsequent 1,2-alkyl shift.
Starting 2-hydroxy-2-alkynylcarbonyl compounds can be prepared by simple
oxygenation of alkynyl carbonyl compounds using 2-iodoxybenzoic acid (IBX).
S. F. Kirsch, J. T. Binder, C. Liébert, H. Menz, Angew. Chem. Int. Ed.,
2006, 45, 5878-5880.
V. Mamane, T. Gress, H. Krause, A. Fürstner, J. Am. Chem. Soc., 2004,
126, 8654-8655.
Cobalt-catalyzed transformations of cyclic alkenes such as cyclopentene and
cycloheptene with internal alkynes led to a chemoselective Alder-ene or a [2 +
2] cycloaddition reaction depending on the electronic nature of the alkyne and
the bite angle of a bidentate phosphine ligand used.
G. Hilt, A. Paul, J. Treutwein, Org. Lett., 2010,
12, 1536-1539.
Ru(bipy)3Cl2 is a visible light photocatalyst for [2+2]
enone cycloadditions. Various aryl enones participate readily in the formation
of the cyclobutane products, and the diastereoselectivity is excellent. A
mechanism is proposed in which a photogenerated Ru(bipy)3+ complex
promotes one-electron reduction of the enone substrate, which undergoes
subsequent radical anion cycloaddition.
M. A. Ischay, M. E. Anzovino, J. Du, T. P. Yoon, J. Am. Chem. Soc., 2008,
130, 12886-12887.
The reaction of various 1,6-enynes with N2CHSiMe3 in the
presence of RuCl(COD)Cp* as catalyst precursor leads to the general formation of
alkenylbicyclo[3.1.0]hexanes at room temperature in good yield with high
stereoselectivity. The catalytic formation of alkenylbicyclo[3.1.0]hexanes also
takes place in the presence of N2CHCO2Et or N2CHPh.
F. Monnier, C. Vovard-Le Bray, D. Castillo, V. Aubert, S. Dérien, P. H.
Dixneuf, L. Toupet, A. Ienco, C. Mealli, J. Am. Chem. Soc., 2007,
129, 6037-6049.
F. Monnier, C. Vovard-Le Bray, D. Castillo, V. Aubert, S. Dérien, P. H.
Dixneuf, L. Toupet, A. Ienco, C. Mealli, J. Am. Chem. Soc., 2007,
129, 6037-6049.
