Categories: C-C Bond Formation > Cyclic compounds > Cycloalkanes
Synthesis of cyclopentanes
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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.
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.
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 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.
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.
