Categories: C=C Bond Formation >
Synthesis unsaturated esters, amides and carboxylic acids
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α,β-unsaturated compounds (C-C Coupling) |
Recent Literature
Water is an effective medium for the Wittig reaction over a wide range of
stabilized ylides and aldehydes including especially substrates with large
hydrophobic entities. Despite sometimes poor solubility of the reactants, good
yields and high E-selectivities are achieved, and the rate of the
reactions in water is unexpectedly accelerated.
A. El-Batta, C. Jiang, W. Zhao, R. Anness, A. L. Cooksy, M. Bergdahl, J. Org. Chem., 2007,
72, 5244-5259.
A. El-Batta, C. Jiang, W. Zhao, R. Anness, A. L. Cooksy, M. Bergdahl, J. Org. Chem., 2007,
72, 5244-5259.
A mild and efficient one-pot Wittig reaction performed in both water and
sodium dodecyl sulfate (SDS)-water solution in open atmosphere allowed the
synthesis of various α,β-unsaturated esters in good yields.
F. Orsini, G. Sello, T. Fumagalli, Synlett, 2006,
1717-1718.
Ethyl (benzothiazol-2-ylsulfonyl)acetate engaged in the modified Julia
olefination with aldehydes under mild reaction conditions to yield α,β-unsaturated esters.
Aryl aldehydes and aliphatic aldehydes possessing significant chain
branching elements gave trans alkene products with
high stereoselectivity, while straight chain aliphatic
aldehydes gave cis products preferentially.
P. R. Blakemore, D. K. H. Ho, W. M. Nap, Org. Biomol. Chem., 2005, 3, 1365-1368.
A generally applicable, sequential reaction of dichloroesters with various
aldehydes is promoted by active manganese to give α,β-unsaturated esters with
complete control of stereoselectivity. The C-C double bond can be di- or
trisubstituted. A mechanism based on a successive aldol-type reaction/-elimination
is proposed.
J. M. Concellón, H. Rodríquez-Solla, P. Díaz, R. Llaona, J. Org. Chem., 2007,
72, 4396-4400.
The stereoselective
reaction of different aldehydes and ethyl dibromoacetate promoted by SmI2 or
CrCl2 gives
(E)-α,β-unsaturated esters by an an aldol-type
reaction and a subsequent β-elimination reaction.
J. M. Concellon, C. Concellon, C. Mejica, J. Org. Chem., 2005, 70, 6111-6113.
A mild protocol for the Horner-Wadsworth-Emmons reaction of diprotic
phosphonates makes use of a zinc triflate promoter in the presence of mild
tertiary amine bases to produce α,β-unsaturated carboxylic acids and amides.
D. J. Schauer, P. Helquist, Synthesis, 2006, 3654-3660.
D. J. Schauer, P. Helquist, Synthesis, 2006, 3654-3660.
The stereoselective reaction of different aldehydes and dibromoacetic acid
promoted by SmI2 gives (E)-α,β-unsaturated
carboxylic acids. The mechanism is discussed.
J. M. Concellon, C. Concellon, J. Org. Chem., 2006, 71, 1728-1731.
A domino oxidation of primary alcohols gives α,β-unsaturated compounds using the
combination of PCC-NaOAc and stabilized Wittig reagents.
J. Shet, V. Desai, S. Tilve, Synthesis,
2004,
1859-1863.
Stereoselective β-elimination of diastereomeric mixtures of
2-bromo-3-hydroxyesters is achieved by using unactivated manganese and
trimethylsilyl chloride, to yield (E)-α,β-unsaturated esters with total
diastereoselectivity.
J. M. Concellón, H. Rodríguez-Solla, V. del Amo, Synlett,
2006, 315-317.
Deprotonation of a 64:36 mixture of ethyl bromo(diphenylphosphono)acetate and
ethyl dibromo(diphenylphosphono)acetate using NaH as base at 0 °C and subsequent
reaction with various aldehydes provided unsaturated α-bromoesters in good
yields and high E-selectivities.
T. Olpp, R. Brückner, Synthesis,
2004, 2135-2152.
A zinc carbenoid-mediated chain extension of β-dicarbonyl compounds
provides access to α,β-unsaturated-γ-keto esters and amides with complete E selectivity
via an intermediate
zinc enolate, which is treated sequentially with iodine and DBU.
M. D. Ronsheim, C. K Zercher, J. Org. Chem., 2003, 68,
4535-4538.
Among the reported examples of new reactivity of the hypervalent iodine
reagent DMP (Dess-Martin periodinane) are the one-step oxidation of
secondary amides to imides and N-acyl vinylogous carbamates or ureas
and the direct oxidation of benzylic and related primary amines to the
corresponding nitriles.
K. C. Nicolaou, C. J. N. Mathison, Angew. Chem., 2005, 117, 6146-6151.
In the presence of ruthenium-based olefin metathesis catalysts and
triphenylphosphine, α,β-unsaturated aldehydes can be olefinated with
diazoacetates. A tandem transformation of
terminal olefins to 1,3-dienoic olefins in a single operation based on olefin
cross-metathesis and Wittig olefination has been developed.
R. P. Murelli, M. L. Snapper, Org. Lett., 2007,
9, 1749-1752.
