Categories: C=C Bond Formation >
Synthesis of various unsaturated compounds
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α,β-unsaturated compounds (C-C Coupling) |
Recent Literature

A simple three-step single-pot procedure for Z-stereoselective synthesis
of β-monosubstituted acrylonitriles involves olefination of aldehydes with an in
situ generated α-diaminoboryl carbanion species. Various aromatic and aliphatic
aldehydes were smoothly converted into the corresponding (Z)-olefin
products in good yields.
T. Tomioka, Y. Takahashi, T. G. Vaughan, T. Yanase, Org. Lett., 2010,
12, 2171-2173.

An inexpensive homogeneous iron catalyst enables a direct approach to alkenyl
nitriles from allylarenes or alkenes. Three C-H bond cleavages occur under the
mild conditions during this process, involving the cleavage of the allyl C(sp3)-H
bond as the rate-determining step.
C. Qin, N. Jiao, J. Am. Chem. Soc., 2010,
132, 15893-15895.

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. Int. Ed., 2005,
44, 5992-5997.

Reaction of aryl nitriles with potassium ethyl malonate in the presence of zinc
chloride and a catalytic amount of Hünig's base provided β-amino acrylates in
moderate to good yield. Compared to the classical Blaise reaction, this reaction
is safer, devoid of lachrymatory reagent, and is possible with less zinc
chloride.
J. H. Lee, B. S. Choi, J. H. Chang, H. B. Lee, J.-Y. Yoon, J. Lee, H. Shin,
J. Org. Chem., 2007,
72, 10261-10263.

The combination of Mo and cationic Au catalysts dramatically accelerated the
rearrangement of diverse propargyl alcohols to yield α,β-unsaturated compounds
under mild conditions, and high product yields. A practical application to the
highly challenging primary propargyl alcohols and the N-alkynyl amides is
achieved.
M. Egi, Y. Yamaguchi, N. Fujiwara, S. Akai, Org. Lett., 2008,
10, 1867-1870.

A highly stereoselective synthesis of aromatic α,β-unsaturated amides was
achieved by treatment of aromatic α,β-epoxyamides with samarium diiodide.
α,β-epoxyamides are easily prepared by the reaction of enolates derived from
α-chloroamides with carbonyl compounds at -78°C.
J. M. Concellón, E. Bardales, J. Org. Chem., 2003,
5, 9492-9295.

The in situ generated Blaise reaction intermediate, a zinc bromide complex of
β-enaminoester, reacts with various alkynes under mild conditions to afford
α-vinylated β-enaminoesters in good to excellent yields.
Y. S. Chun, Y. O. Ko, H. Shin, S.-g. Lee, Org. Lett., 2009,
11, 3414-3417.
