Categories: C-C Bond Formation > Cyclic compounds > Cycloalkenes
Synthesis of cyclopentenes
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Recent Literature
An allylic alkylation/ring-closing metathesis domino process is catalyzed by the
combination of a palladium and a ruthenium catalyst. This study demonstrates the
compatibility of the two catalytic systems. Evidence for Grubbs' catalysts
activity in allylic alkylation is also reported.
C. Kammerer, G. Prestat, T. Gaillard, D. Madec, G. Poli, Org. Lett., 2008,
10, 405-408.
A nucleophile-catalyzed asymmetric [3+2] cycloaddition of allenes with enones is
described. The method has also been applied to reactions of trisubstituted
olefins, thereby generating quartenary and tertiary stereocenters.
J. E. Wilson, G. C. Fu, Angew. Chem. Int. Ed., 2006, 45,
1426-1429.
An efficient cycloallylation of mono-enone mono-allylic carbonates is achieved
upon exposure to tributylphosphine and 1 mol % Pd(Ph3P)4.
This transformation combines the nucleophilic features of the
Morita-Baylis-Hillman reaction with the electrophilic features of the
Trost-Tsuji reaction.
B. G. Jellerich, J.-R. Kong, M. J. Krische, J. Am. Chem. Soc., 2003,
125, 7758-7759.
Using a catalytic amount of trialkylphosphines, alkyl halides undergo
efficient intramolecular Morita-Baylis-Hillman cyclization.
M. E. Krafft, K. A. Seibert, Synlett, 2006,
3334-3336.
An organomediated, intramolecular Morita-Baylis-Hillman reaction of molecules
bearing allylic leaving groups as the electrophilic partner provided a facile,
high yielding, straightforward synthesis of densely functionalized cyclic
molecules.
M. E. Krafft, T. F. N. Haxell, J. Am. Chem. Soc., 2005, 127,
10168-10169.
Conversion of unsaturated ketones and aldehydes derived from the
cycloisomerization of primary and secondary propargyl diynols in the presence of
[CpRu(CH3CN)3]PF6 to 1-azatrienes and a
subsequent electrocyclization-dehydration provides pyridines with excellent
regiocontrol.
B. M. Trost, A. C. Gutierrez, Org. Lett., 2007,
9, 1473-1476.
An enantioselective synthesis of α,α-disubstituted cyclopentenes proceeds via a
chiral enol generated in situ from an α,β-unsaturated aldehyde and a chiral N-heterocyclic
carbene catalyst. This reactive enol undergoes addition to one of two
enantiotopic ketones to afford an optically active β-lactone. Depending on the
substitution, a decarboxylation produces the cyclopentene products in high ee.
M. Wadamoto, E. M. Philipps, T. E. Reynolds, K. A. Scheidt, J. Am. Chem. Soc.,
2007,
129, 10098-10099.
An oxidation-methylenation one-pot procedure in the presence different catalysts
produced terminal alkenes in high yields. A methylenation-ring-closing process
for the synthesis of cyclic alkenes from carbonyl derivatives was even expanded
with an initial oxidation to allow the use of alcohols as substrates.
H. Lebel, V. Paquet, J. Am. Chem. Soc., 2004, 126,
11152-11153.
Ruthenium carbene complexes catalyze ring closing metathesis (RCM) and a
subsequent hydrogenation after activation with sodium hydride. Hydrogenation of
cyclopentenols proceeds smoothly at ambient temperature and under 1 atm of
hydrogen in toluene.
B. Schmidt, M. Pohler, Org. Biomol. Chem., 2003, 1,
2512-2517.
The GaCl3-catalyzed skeletal reorganization of enynes is simple and
provides a diverse range of dienes in good to high yields. The reaction of
enynes proceeds in a stereospecific manner with respect to the geometry of the
olefin moiety.
N. Chatani, H. Inoue, T. Kotsuma, S. Murai, J. Am. Chem. Soc., 2002,
124, 10294-10295.
Cycloalkenes can be efficiently prepared by a new Ru-catalyzed decarbonylative
cyclization of terminal alkynals. Under appropriate conditions,
cycloisomerizations to conjugated aldehydes may be observed. Both processes
involve catalytic Ru vinylidenes.
J. A. Varela, C. Gonzlez-Rodríguez, S. G. Rubín, L. Castedo, Carlos Saá, J.
Am. Chem. Soc., 2006, 128, 9576-9577.
J. A. Varela, C. Gonzlez-Rodríguez, S. G. Rubín, L. Castedo, Carlos Saá, J.
Am. Chem. Soc., 2006, 128, 9576-9577.
Trapping of β,γ-alkynyl aldehydes, generated in situ by treatment of alkynyloxiranes with a
catalytic amount of Sc(OTf)3 or BF3ˇOEt2, by a variety of allyl nucleophiles affords homopropargylic
homoallylic alcohols in good yield and selectivity. Subsequent enyne metathesis
gives functionalized vinylcyclopentenols.
L. Wang, M. L. Maddess, M. Lautens, J. Org. Chem., 2007,
72, 1822-1825.
The use of cationic silver (AgSbF4) as a catalyst for intra- and
intermolecular alkyne-carbonyl coupling is described.
J. U. Rhee, M. J. Krische, Org. Lett., 2005, 7, 2493-2495.
Iodocyclopentenes are formed at room temperature upon
iodonium-promoted 5-endo-dig carbocyclization of
δ-alkynyl-β-ketoesters with I2. Cyclizations
involving terminal and substituted (alkyl, aryl, Br, I) alkynes were accessed.
J. Barluenga, D. Palomas, E. Rubio, J. M. Gonzáles, Org. Lett., 2007,
9, 2823-2826.
A sequence of two gold(I)-catalyzed isomerization steps allows the synthesis of
functionalized acetoxy bicyclo[3.1.0]hexenes from 5-en-2-yn-1-yl acetates.
Acetoxy bicyclo[3.1.0]hexene products can be further transformed to
2-cycloalkenones by simple methanolysis.
A. Buzas, F. Gagosz, J. Am. Chem. Soc., 2006, 128,
12614-12615.
