ORGN 134 |
| The Sonogashira coupling was originally developed to couple a terminal alkyne with an aryl or vinyl iodide under anaerobic and anhydrous conditions using a palladium catalyst, a copper(I) cocatalyst, and an excess of a secondary or tertiary alkyl amine. This reaction has proven to be extremely valuable for many multi-component, one-pot syntheses, including the synthesis of ynones, halofurans, benzofurans, lactams, pyrimidines, and enaminones for pharmaceuticals, as well as liquid crystalline polymers and optical materials. Although there have been many attempts to improve the palladium catalyst, it still often has the drawbacks of the need to store it under nitrogen and being sensitive to air. The long reaction times and the limited choice of reaction medium are also sited often as weaknesses of the Sonogashira coupling. In addition, the copper co-catalyst has drawbacks, because it is difficult and expensive to recover, especially for large-scale reactions. Therefore, we are reporting the development of an ionic liquid catalyst system which allows the alkynylation of aryl and alkenyl halides without the use of copper salts as catalysts. Reaction progress was followed using TLC, and all products have been characterized using 1H NMR, 13C NMR, and FTIR. |
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Physical Organic Chemistry, Combinatorial and Process Chemistry, New Reactions and Methodology, Peptides, Proteins and Amino Acids
8:00 PM-10:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A, Poster
Division of Organic Chemistry |