Esters copper-catalyzed coupling

Synthesis of Functionalized Enynes by Palladium/Copper-catalyzed Coupling Reactions of Acetylenes with (Z)-2,3-Dibromopropenoic Acid Ethyl Ester (Z)-2-Bromo-5-(trimethylsilyl)-2-penten-4-ynoic Acid Ethyl Ester. 

SYNTHESIS OF FUNCTIONALIZED ENYNES BY PALLADIUM/COPPER-CATALYZED COUPLING REACTIONS OF ACETYLENES WITH (Z)-2,3-DIBROMOPROPENOIC ACID ETHYL ESTER (Z)-2-BROMO-5-(TRIMETHYLSILYL)-2-PENTEN-4-YNOIC... 

The copper-catalyzed coupling of glycolic acids with aryl iodides has been accomplished using common copper catalysts (Scheme 2.54) [79], This was a chemoselective transformation that resulted in the preferential formation of the alkyl aryl ether instead of the ester. The carboxylic acid was retained in the product and was able to be further transformed in subsequent reactions. The electronic composition of the aryl iodide did not significantly influence the outcome of the reaction, and a range of electron-rich and electron-poor arenes were well tolerated by the chemistry. 

Recently, the Chan-Lam reaction was also adapted for the synthesis of aniline derivatives. Indeed, in 2009, Fu et al. described the base- and Ugand-free copper-catalyzed coupling of arylboronic acids with aqueous ammonia (Scheme 30) [234]. This very simple system used 10% of CuzO under air at room temperature and affords the corresponding aniline derivatives in very good yields. The reaction can also be carried out from arylboronic acid esters. A related reaction, performed in water with CUSO4.5H2O as catalyst, was more recently reported by Wu [235]. Fu et al. also reported a quite similar system [236]. 

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