Categories: C-C Bond Formation > Cyclic compounds > Cycloalkenes
Synthesis of cyclopentenes
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Recent Literature
The reaction of organocerium reagents, generated in situ from aryl and
heteroaryl lithium compounds, with cycloalkanones proceeds cleanly to provide
alkoxides. Addition of MsCl or SOCl2 with DBU gave aryl-substituted
cycloalkenes in good yields. A short total synthesis of (±)-laurokamurene B is
described.
J. Tallineau, G. Bashiardes, J.-M. Coustard, F. Lecornué, Synlett, 2009,
2761-2764.
In situ generation of allylic boronates by iridium-catalyzed borylation of
cyclic alkenes in the presence of additives, such as methylimidazole and DBU,
followed a reaction with aldehydes allows the synthesis of stereodefined
homoallylic alcohols. Cycloalkenes without additives as well as acyclic
substrates gave vinylic boronates, which were coupled with organohalides in a
Suzuki-Miyaura sequence.
V. J. Olsson, K. J. Szabó, J. Org. Chem., 2009,
74, 7715-7723.
V. J. Olsson, K. J. Szabó, J. Org. Chem., 2009,
74, 7715-7723.
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 highly enantioselective Rh-catalyzed asymmetric allylic substitution allows
the desymmetrization of meso cyclopent-2-ene-1,4-diethyl dicarbonates.
Depending on the ligand, each of two regioisomeric products can be obtained in
good yield and excellent enantioselectivity. Whereas bisphosphine P-Phos ligands
form trans-1,2-arylcyclopentenols, Segphos ligands lead predominantly to
trans-1,4-arylcyclopentenols.
F. Menard, D. Perez, D. S. Roman, T. M. Chapman, M. Lautens, J. Org. Chem., 2010,
75, 4056-4068.
A P-cyclohexyl substituted ferrocenophane catalyst affords high levels of
asymmetric induction in the organocatalytic [3 + 2] annulation reaction between
allenes and electron-poor olefins.
A. Voituriez, A. Panossian, N. Fleury-Brégeot, P. Retailleau, A. Marinetti, J. Am. Chem. Soc., 2008,
130, 14030-14031.
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 method allows a stereospecific synthesis of trans-substituted
cyclopentene derivatives via the ring-opening rearrangement of readily available
MCP alkenyl derivatives in good yields. This transformation might proceed
through a fast concerted pericyclic process rather than a simple radical pathway
or an ionic pathway.
X.-Y. Tang, M. Shi, J. Org. Chem., 2010,
75, 902-905.
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.
N-Heterocyclic carbene/Lewis acid cooperative catalysis provides access
to cis-1,3,4-trisubstituted cyclopentenes from enals and chalcone
derivatives with high levels of diastereoselectivity and enantioselectivity. The
presence of Ti(OiPr)4 as Lewis acid enables an efficient
substrate preorganization, which translates into high levels of
diastereoselectivity.
B. Cardinal-David, D. E. A. Raup, K. A. Scheidt, J. Am. Chem. Soc., 2010,
132, 5345-5347.
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. González-Rodríguez, S. G. Rubín, L. Castedo, Carlos Saá, J.
Am. Chem. Soc., 2006, 128, 9576-9577.
J. A. Varela, C. González-Rodríguez, S. G. Rubín, L. Castedo, Carlos Saá, J.
Am. Chem. Soc., 2006, 128, 9576-9577.
TFA-promoted exo carbocyclizations of nonterminal alkynals gave good to
excellent yields of exo cycloalkenones. On the other hand, terminal
5-alkynals gave endo carbocyclizations to cyclohexenones. These
carbocyclizations can be considered as tandem alkyne hydration/aldol
condensation processes.
C. González-Rodríguez, L. Escalante, J. A. Varela, L. Castedo, C. Sáa, Org. Lett., 2009,
11, 1531-1533.
Trapping of β,γ-alkynyl aldehydes, generated in situ by treatment of alkynyloxiranes with a
catalytic amount of Sc(OTf)3 or BF3·OEt2, 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.
