ORGANIC
LETTERS
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Vol. XX, No. XX
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Arylations of Substituted Enamides by
Aryl Iodides: Regio- and Stereoselective
Synthesis of (Z)‑β-Amido-β-Arylacrylates
Quan Gou, Bin Deng, Hongbin Zhang, and Jun Qin*
School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan,
650091, P. R. China
Received August 5, 2013
ABSTRACT
Arylations of substituted enamides by aryl iodides were achieved for the first time via an unusual PdCl2(COD)/Ag3PO4 catalytic system. A broad
range of (Z)-β-amido-β-arylacrylates were prepared regio- and stereoselectively in a highly efficient manner.
Palladium-catalyzed Heck arylation, one of the most
useful reactions to construct carbonÀcarbon bonds, in-
volves the coupling of aryl halides/pseudohalides with
olefins.1 Heck arylations were typically catalyzed by Pd(0)
or Pd(II) with an added phosphine ligand and operating
under a Pd(0)/Pd(II) catalytic cycle with the assistance of
base to complete the cycle. In a program directed toward
synthesis of enamides,2 especially trisubstituted enamide
β-amido-β-arylacrylates, substrate commonly used to pre-
pare valuable chiral β-amino acid through asymmetric
hydrogenation,3 we noticed that classic methods of con-
densing β-ketoester with amino source to prepare this
substrate suffer from low efficiency and poor stereocontrol
of olefin geometry in general.3d,f Although progress
has been made in palladium-catalyzed Heck arylation
of enamide by using aryl triflates as arylation partner or
through ionic liquid-promoted protocol as alternative
approaches to address these problems, only unsubstituted
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r
10.1021/ol402215f
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