Categories: C-C Bond Formation > Carbocyclic compounds > Cycloalkenes
Synthesis of cycloheptenes and higher homologues
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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.
A regioselective oxidative allylic C(sp3)-H arylation of readily
available unactivated terminal and internal olefins with a broad range of
heteroaryl boronic acids is catalyzed by cheap, abundant, and nontoxic Cu2O.
This method does not require traditional coupling partners with preinstalled
leaving groups at the allylic position, thus offering an alternative method to
allylic arylation.
S. Pal, M. Cotard, B. Gérardin, C. Hoarau, C. Schneider, Org. Lett.,
2021, 23, 3130-3135.
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.
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.
Rh-catalyzed [5 + 2] cycloadditions of 1-(2-methyoxyethoxy)-1-vinylcyclopropane
as a five-carbon component to alkynes provide cycloheptenones in many cases in
minutes and in very good isolated yields. The procedure is readily conducted on
a small or large scale.
P. A. Wender, A. J. Dyckman, C. O. Husfeld, M. J. C. Scanio,
Org. Lett., 2000, 2, 1609-1611.
[ReBr(CO)3(thf)]2 catalyzes the reaction of a
1,3-dicarbonyl cyclic compound with an acetylene to give a medium-sized cyclic
compound in excellent yield. By using isocyanide as an additive, the insertion
of acetylenes into a carbon-carbon single bond occurs under mild conditions.
Y. Kuninobu, A. Kawata, K. Takai, J. Am. Chem. Soc., 2006, 128,
11368-11369.