Categories: C-C Bond Formation > Cyclic compounds > Cyclic enones
Synthesis of cyclohexenones
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Recent Literature
Wittig reaction of aldehydes with (cyclopropylmethyl)triphenylphosphonium
bromide delivered alkenyl cyclopropanes. UV irradiation in the presence of
Fe(CO)5 converted these alkenyl cyclopropanes to 2-substituted
cyclohexenones. This approach enabled a three-step synthesis of the tricyclic
core of estrone methyl ether.
D. F. Taber, R. B. Sheth, J. Org. Chem., 2008,
73, 8030-8032.
The gold(I) complex MeAuPPh3 is a highly effective catalyst for the
hydrative cyclization of 1,6-diynes to yield 3-methyl hex-2-enone derivatives
with very good yield. A mechanism is proposed.
C. Zhang, D.-M. Cui, L.-Y. Yao, B.-S. Wang, Y.-Z. Hu, T. Hayashi, J. Org. Chem., 2008,
73, 7811-7813.
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.
Brřnsted acid-mediated cyclizations of siloxyalkynes with simple arenes and
alkenes afforded substituted tetralone and cyclohexenone derivatives. A wide
range of substrates can be employed in these carbocyclizations.
L. Zhang, S. A. Kozmin, J. Am. Chem. Soc., 2004, 126,
10204-10205.
Chiral BINOL-derived Brřnsted acids catalyze a highly enantioselective
asymmetric Morita-Baylis-Hillman (MBH) reaction of cyclohexenone with aldehydes.
The reaction requires 2-20 mol% of the chiral Brřnsted acid and
triethylphosphine as the nucleophilic promoter.
N. T. McDougal, S. E. Schaus, J. Am. Chem. Soc., 2003, 125, 12094-12095.
A mild, palladium-catalyzed intramolecular oxidative alkylation of various
ζ-alkenyl β-diketones and ζ-alkenyl β-keto esters in the presence of CuCl2
at room temperature formed the corresponding 2-cyclohexenones in high yield.
T. Pei, X. Wang, R. A. Widenhoefer, J. Am. Chem. Soc., 2003,
125, 648-649.
A solvent-free ytterbium(III) triflate promoted, zinc(II) chloride catalyzed
Conia-ene reaction allows the construction of cyclic enones. In the presence of
zinc(II) chloride and ytterbium(III) triflate, a variety of linear β-alkynic
β-keto esters and β-diketones were cyclized under neat conditions in good yields.
The selectivity toward five- or six-membered-ring carbocycles depends on
substituents at the terminal alkynes.
Y. Liu, R.-J. Song, J.-H. Li, Synthesis, 2010, 3663-3669.
Y. Liu, R.-J. Song, J.-H. Li, Synthesis, 2010, 3663-3669.
A highly stereoselective tandem Michael addition-Wittig reaction of
(3-carboxy-2-oxopropylidene)triphenylphosphorane and α,β-unsaturated aldehydes
gives multifunctional 6-carboxycyclohex-2-en-1-ones in excellent diastereo- and
enantioselectivities by employing the combined catalysis of a bulky chiral
secondary amine, LiClO4, and DABCO.
Y.-k. Liu, C. Ma, K. Jian, T.-Y. Liu, Y.-C. Chen, Org. Lett., 2009,
11, 2848-2851.
An efficient and regioselective Yb(OTf)3-promoted palladium-catalyzed
oxidative cyclization of γ-heteroalkenyl β-keto amides has been developed. Under
simple aerobic condition, various six-, seven-, and eight-membered-ring N-
and O-heterocycles were obtained in excellent yield.
K.-T. Yip, J.-H. Li, O.-Y. Lee, D. Yang, Org. Lett., 2005, 7,
5717-5719.
A scalable, direct functionalization of various quinones with several boronic
acids proceeds readily at room temperature in an open flask using catalytic
silver(I) nitrate in the presence of a persulfate co-oxidant. The scope with
respect to quinones is broad, with a variety of alkyl- and arylboronic acids
undergoing efficient cross-coupling.
Y. Fujiwara, V. Domingo, I. B. Seiple, R. Gianatassio, M. Del Bel, P. P. S.
Baran, J. Am. Chem. Soc., 2011,
133, 3292-3295.
