Categories: C=C Bond Formation >
Synthesis of various unsaturated compounds
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α,β-unsaturated compounds (C-C Coupling) |
Recent Literature
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.
A manganese pincer complex catalyzes an
unprecedented acceptorless dehydrogenative coupling of alkyl sulfones with
alcohols to provide highly functionalized vinyl sulfones in good yields. Several functional groups including bromides and iodides are tolerated under the
reaction conditions. This environmentally benign reaction produces
dihydrogen and water as byproducts.
S. Waiba, M. K. Barman, B. Maji, J. Org. Chem., 2019, 84,
973-982.