Categories: Synthesis of O-Heterocycles, C-O Bond Formation, Synthesis of cyclic ethers >
Synthesis of tetrahydrofurans
Recent Literature
The platinum-catalyzed hydroalkoxylation of γ- and δ-hydroxy olefins
tolerated various substitution patterns and a number of functional groups
including pivaloate and acetate esters, amides, silyl and benzyl ethers, and
pendant hydroxyl and olefinic groups.
H. Qian, X. Han, R. A. Widenhoefer, J. Am. Chem. Soc.,
2004, 126, 9536-9537.
The reaction of tertiary 1,4- and 1,5-diols with cerium ammonium nitrate at room
temperature gives tetrahydrofuran and tetrahydropyran derivatives in high yield
and stereoselectivity. Various fragrant compounds have been synthesized using
this method.
E. J. Alvarez-Manzaneda, R. Chabouna, E. Alvarez, E. Cabrera, R.
Alvarez-Manzaneda, A. Haidour, J. M. Ramos, Synlett, 2006,
1756-1758.
Silver(I) triflate catalyzes intramolecular additions of hydroxyl or carboxyl groups to olefins
in good to excellent yields for a range of substrates under relatively mild conditions. This
reaction is one of the simplest methods to construct cyclic ethers or
lactones.
C.-G. Yang, N. W. Reich, Z. Shi, C. He, Org. Lett.,
2005, 7, 4553-4556.
A new, stereoselective, palladium-catalyzed method for the synthesis of substituted
tetrahydrofurans from γ-hydroxy alkenes and aryl bromides forms both a C-C and a C-O bond with
diastereoselectivities of up to >20:1. The reactions probably proceed via the intramolecular insertion of an olefin
into a Pd(Ar)(OR) intermediate.
J. P. Wolfe, M. A. Rossi, J. Am. Chem. Soc.,
2004, 126, 1620-1621.
The Au(I)-catalyzed intramolecular hydroamination of N-allenyl
carbamates was effective for the formation of various cyclic amines. γ-Hydroxy
and δ-hydroxy allenes underwent Au-catalyzed intramolecular
hydroalkoxylation to form the corresponding
oxygen heterocycles in good yield. 2-Allenyl indoles
underwent Au-catalyzed intramolecular hydroarylation to form 4-vinyl tetrahydrocarbazoles in good yield.
Z. Zhang, C. Liu, R. E. Kinder, X. Han, H. Qian, R. A. Widenhoefer, J. Am. Chem. Soc.,
2006, 128, 9066-9073.
Several Pd-catalyzed oxidative cyclizations proceed in excellent yield under
simple aerobic conditions. Importantly, this system provided entry into
enatioselective catalysis with a readily available Pd-sparteine complex.
R. M. Trend, Y. K. Ramtohul, E. M. Ferreira, B. Stoltz,
Angew. Chem. Int. Ed., 2003, 42, 2892-2895.
Oxidative
bromination of different types of olefins using Selectfluor/KBr afforded addition,
monobromo-substituted, or Hunsdiecker-Borodin reaction products in good yields.
C. Ye, J. M. Shreeve, J. Org. Chem., 2004, 69, 8561-8563.
A new methodology for the cycloisomerization of dienes using a Grubbs carbene
complex and trimethylsilyl vinyl ether has been established. The utility of this
reaction was demonstrated by in the synthesis of exo-methylene
heterocyclic compounds, which could act as key intermediates for
pharmacologically active compounds.
Y. Terada, M. Arisawa, A. Nishida, Angew. Chem. Int. Ed., 2004,
43,
4063-4067.
Palladium-catalyzed inter- and intramolecular enyne coupling
reactions were developed. The
reaction involves the acetoxypalladation of the alkyne, followed by the
insertion of the alkene and the protonolysis of the carbon-palladium bond. The coupling
allows the construction of synthetically important carbo- and
heterocycles.
L. Zhao, X. Lu, W. Xu, J. Org. Chem., 2005, 70, 4059-4063.
An intramolecular iodo-aldol cyclization of prochiral α-substituted enoate
aldehydes and ketones produces hetero- and carbocycles containing quaternary centers adjacent
to secondary or tertiary centers. The reactions occur in good yields and are
highly trans-selective with hydroxyl and iodomethyl
groups on opposite faces of the ring system.
F. Douelle, A. S. Capes, M. F. Greaney, Org. Lett., 2007,
9, 1931-1934.
Catalytic hydrogenation of acetylenic aldehydes using a chirally modified
cationic rhodium catalysts enables highly enantioselective reductive
cyclization to afford cyclic allylic alcohols. Using an achiral
hydrogenation catalyst, some chiral racemic acetylenic aldehydes engage in
highly syn-diastereoselective reductive cyclizations.
J. U. Rhee, M. J. Krische, J. Am. Chem. Soc., 2006, 128, 10674-10675.
Treatment of 3-[(alkoxycarbonyl)alkyl]-substituted conjugated cycloalkenones
with diisobutylaluminum hydride at -78 °C followed by acid quenching
furnishes spiro ethers, whereas the corresponding 3-(carboxyalkyl)-substituted
cycloalkenones generate spiro lactones upon reaction with sodium borohydride
at 30 °C followed by acid quenching.
M.-C. P. Yeh, Y.-C. Lee, T.-C. Young, Synthesis, 2006, 3621-3624.
Allenylidene-ruthenium complexes on protonation with HOTf are rearranged to
indenylidene-ruthenium complexes, which are efficient catalyst precursors for
ring-opening metathesis polymerization, ring-closing metathesis and enyne
metathesis of a variety of substrates.
R. Castarlenas, C. Vovard, C. Fischmeister, P. H. Dixneuf, J. Am. Chem. Soc.,
2006, 128, 4079-4089.
A chiral iridium diphosphine complex catalyzes an enantioselective
intramolecular Pauson-Khand-type reaction to give various chiral bicyclic
cyclopentenones. A low partial pressure of carbon monoxide is important to
achieve excellent enantioselectivity.
T. Shibata, N. Toshida, M. Yamasaki, S. Maekawa, K. Takagi, Tetrahedron, 2005,
61, 9974-9979.
An entrapped Rh catalyst derived by
a sol-gel process (see article for method), has been used in a Pauson-Khand reaction
under mild conditions. The catalyst can be reused at
least 10 times without losing activity. This catalytic system is not effective
for intermolecular reactions.
K. H. Park, S. U. Song, Y. K. Chung, Tetrahedron
Lett., 2003, 44, 2827-2830.
A new Pd-catalyzed oxidation reaction for the stereospecific conversion of
enynes into cyclopropyl ketones proceeds with net inversion of geometry with
respect to the starting olefin. This result is consistent with a mechanism in
which the key cyclopropane-forming step involves nucleophilic attack of a
tethered olefin onto the PdIV-C bond.
L. L. Welbes, T. W. Lyons, K. A. Cychosz, M. S. Sanford, J. Am. Chem. Soc., 2007,
129, 5836-5837.
The reaction of various 1,6-enynes with N2CHSiMe3 in the
presence of RuCl(COD)Cp* as catalyst precursor leads to the general formation of
alkenylbicyclo[3.1.0]hexanes at room temperature in good yield with high
stereoselectivity. The catalytic formation of alkenylbicyclo[3.1.0]hexanes also
takes place in the presence of N2CHCO2Et or N2CHPh.
F. Monnier, C. Vovard-Le Bray, D. Castillo, V. Aubert, S. Dérien, P. H.
Dixneuf, L. Toupet, A. Ienco, C. Mealli, J. Am. Chem. Soc., 2007,
129, 6037-6049.
F. Monnier, C. Vovard-Le Bray, D. Castillo, V. Aubert, S. Dérien, P. H.
Dixneuf, L. Toupet, A. Ienco, C. Mealli, J. Am. Chem. Soc., 2007,
129, 6037-6049.
A mild, complete hydrogenation of aromatic rings catalyzed by heterogeneous 10%
Rh/C proceeds at 80 °C in water under 5 atm of H2 pressure and is
applicable to the hydrogenation of various carbon and heteroaromatic compounds
such as alkylbenzenes, biphenyls, pyridines and furans.
Maegawa, A. Akashi, H. Sajiki, Synlett,
2006, 1440-1442.
 |
Diastereoselective and Enantioselective Construction of Cyclic Ethers Stereocontrolled Construction of Cyclic Ethers Enantioselective Construction of Naturally-Occurring Cyclic Ethers |
