Categories: C-C Bond Formation > Carbocyclic compounds > Cyclic alcohols
Synthesis of cyclopentanols
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Recent Literature
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 combination of hydrogen atom transfer photocatalysis and boronic acid mediated
transient thermodynamic control enables a selective epimerization of cyclic
trans
diols to provide the less stable cis products. A range of substitution patterns and
ring sizes are amenable to selective isomerization, including stereochemically
complex polyols.
C. J. Oswood, D. W. C. MacMillan, J. Am. Chem. Soc.,
2022, 144, 93-98.
Cyclizations of allenyl aldehydes and intermolecular couplings of allenes and
aldehydes provide homoallylic alcohols. The couplings and cyclizations involve
the use of diorganozinc reagents as reducing agents and Ni(COD)2 as
the catalyst.
M. Song, J. Montgomery, Tetrahedron, 2005,
61, 11440-11448.
The CoI2(dppe)-catalyzed diastereoselective reductive [3 + 2]
cycloaddition of allenes and enones gives cyclopentanols in very good yields in
the presence of zinc, zinc iodide, and water.
H.-T. Chang, T. T. Jayanth, C.-H. Cheng, J. Am. Chem. Soc., 2007,
129, 4166-4167.
An intermolecular pinacol coupling of aromatic or aliphatic carbonyl compounds catalyzed by a complex of samarium diiodide (SmI2) with tetraglyme in the presence of Me2SiCl2 and Mg is described. High diastereoselectivity has been achieved in reactions with aliphatic and aromatic aldehydes. De values of up to 99% have been achieved in intramolecular pinacol coupling reactions.
H. C. Aspinall, N. Greeves, C. Valla, Org. Lett., 2005, 7, 1919-1922.
An efficient lithium amide-induced intramolecular cyclopropanation of
bishomoallylic and trishomoallylic epoxides is described. The methodology is
used in an asymmetric synthesis of sabina ketone.
D. M. Hodgson, Y. K. Chung, J.-M. Paris, J. Am. Chem. Soc., 2004,
126, 8654-8655.
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.
Stirring α,β-unsaturated α-diketones in the presence of activated silica gel
results in cyclization to α-hydroxycyclopentenones in good yield. The reaction
is sensitive to the mode of stirring and proceeds more rapidly in the presence
of triethylamine consistent with a Nazarov reaction proceeding through the enol
tautomer.
E. A. Uhrich, W. A. Batson, M. A. Tius, Synthesis, 2006,
2139-2142.
A [6 + 2] annulation that involves the combination of β-alkenoyl acylsilanes
and a vinyllithium derivative enables in one operation and a stereoselective
manner the construction of eight-membered ring systems containing useful
functionalities for further synthetic elaboration from readily available six-
and two-carbon components.
K. Takeda, H. Haraguchi, Y. Okamoto, Org. Lett.,
2003, 5, 3705-3707.
