Categories: Synthesis of O-Heterocycles, C-O Bond Formation >
Synthesis of lactones and related compounds
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Recent Literature
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 and reliable method for the direct construction of biologically important
aryl lactones and phthalides from carboxylic and benzoic acids is based on
selective benzylic C-H abstraction in the presence of hypervalent iodine(III)
reagents and KBr.
T. Dohi, N. Takenaga, A. Goto, A. Maruyama, Y. Kita, Org. Lett., 2007,
9, 3129-3132.
The hypervalent iodine reagent PIFA promotes the efficient intramolecular
electrophilic cyclization of easily accessible alkynylamides and alkynyl
carboxylic acids, leading to pyrrolidinone and lactone skeletons, respectively.
A synthetic study and a mechanistic proposal for these transformations are
presented.
I. Tellitu, S. Serna, M. T. Herrero, I. Moreno, E. Domínguez, R. SanMartin, J. Org. Chem., 2007,
72, 1526-1529.
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.
A general, efficient, and convenient cyclization of alkynes bearing carboxylic
acids to the corresponding γ-alkylidene-γ-butyrolactones in the presence of
commercially available Au2O3 shows a high degree of
chemo-, regio-, and stereoselectivity. The 5-exo mode of cyclization and anti
auration are a general trend for the Au2O3 catalyst.
P. Y. Toullec, E. Genin, S. Antoniotti, J.-P. Genęt, V. Michelet, Synlett, 2008,
707-711.
A highly efficient gold-catalyzed cyclization reaction of various
functionalized acetylenic leads to γ-lactones in good to excellent yields.
The reaction conditions are compatible with several functional groups, such
as ester, alkene, alkyne, chloro, and free or protected alcohol.
E. Genin, P. Y. Toullec, S. Antioniotti, C. Brancour, J.-P. Genęt, V.
Michelet, J. Am. Chem. Soc.,
2006, 128, 3112-3113.
A mechanistic investigation on the effect of substrate on stereoselectivity in the triflic acid-catalyzed allylboration
reaction between 2-alkoxycarbonyl allylboronates and aldehydes confirms the
involvement of a carbocation intermediate as the source of stereochemical
inversion. This methodology allows a facile access to β,γ-disubstituted
five-membered ring lactones.
T. G. Elford, Y. Arimura, S. H. Yu, D. G. Hall, J. Org. Chem., 2007,
72, 1276-1284.
T. G. Elford, Y. Arimura, S. H. Yu, D. G. Hall, J. Org. Chem., 2007,
72, 1276-1284.
Depending on the strength of a Lewis or Brřnsted acid catalyst, borate intermediates resulting from the crotylboration of aliphatic aldehydes
with ester-containing crotylboronates form either γ-substituted-α-alkylidene-γ-butyrolactones
via oxonia cope
rearrangement-lactonization or
β,γ-disubstituted-α-methylene-γ-butyrolactones via lactonization.
P. V. Ramachandran, D. Pratihar, Org. Lett., 2007,
9, 2087-2090.
P. V. Ramachandran, D. Pratihar, Org. Lett., 2007,
9, 2087-2090.
The Reformatsky reaction of α-hydroxy ketones with indium enolates furnished
highly diastereoselective lactones, while α-alkoxy ketones gave acyclic
esters in moderate selectivities. A boat-type of chelated bicyclic
transition state involving highly diastereoselective construction of three
contiguous stereogenic centers is proposed.
S. A. Babu, M. Yasuda, Y. Okabe, I. Shibata, A. Baba, Org. Lett.,
2006, 8, 3029-3032.
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.
A mild, enantioselective
hetero-Diels-Alder (HDA) reaction of the Brassard diene with aldehydes in the
presence of a chiral titanium(IV) tridentate Schiff-base complexe has been
developed. The
mechanism is discussed.
Q. Fan, L. Lin, J. Liu, Y. Huang, X. Feng, Eur. J. Org. Chem., 2005,
3542-3552.
The Brřnsted acid catalyzed formal insertion of an isocyanide into a C-O bond
of various acyclic and cyclic acetals can be applied to form α-alkoxy imidates.
Functional groups, such as nitro, cyano, halogen, ester, and alkoxy groups, are
tolerant to the reaction conditions employed. The course of the reaction is
highly dependent on the structure of the isocyanide.
M. Tobisu, A. Kitajima, S. Yoshioka, I. Hyodo, M. Oshita, N. Chatani, J. Am. Chem. Soc.,
2007,
129, 11431-11437.
The synthesis of a planar-chiral bisflavin catalyst (1) and its use
in asymmetric Bayer-Villiger-Oxidations is described.
S. Murahashi, S. Ono, Y. Imada, Angew. Chem. Int. Ed., 2002, 41,
2366-2368.
The regioselective opening of Bn2N-α-methylserine-β-lactone
with organocuprates gave enantiopure α-methyl amino acids in excellent yields.
N. D. Smith, A. M. Wohlrab, M. Goodman, Org. Lett., 2005, 7, 255-258.
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.
