Copper-Catalyzed Synthesis of 1,3-Enynes
Craig G. Bates, Pranorm Saejueng and D. Venkataraman*
*Department of Chemistry, University of Massachusetts-Amherst, 710 North
Pleasant Street, Amherst, Massachusetts 01003, Email: dv
chem.umass.edu
C. G. Bates, P. Saejueng, D. Venkataraman, Org. Lett., 2004, 6, 1441-1444.
DOI: 10.1021/ol049706e
Abstract
A copper(I)-catalyzed coupling of alkynes with vinyl iodides affords various enynes in good to excellent yields, tolerates a variety of functional groups, and does not require the use of expensive additives.
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Details
The document reports a copper(I)-catalyzed method for synthesizing 1,3-enynes, which are important in various naturally occurring and biologically active compounds. This method is notable for its high yields, tolerance of various functional groups, and the absence of expensive additives or palladium. The procedure involves the cross-coupling of vinyl iodides and acetylenes, optimized using phenylacetylene and (Z)-ethyl-3-iodoacrylate as test reactions. The optimal conditions identified include using [Cu(bipy)PPh3Br] as the catalyst and K2CO3 as the base, achieving a 99% yield. The method is effective for a wide range of aryl acetylenes and vinyl iodides, retaining the stereochemistry of the starting materials. For challenging substrates, [Cu(phen)(PPh3)2]NO3 and Cs2CO3 are recommended. This protocol is advantageous due to its mild conditions, broad substrate scope, and high efficiency, making it a valuable alternative to traditional palladium-catalyzed methods. The research was supported by various grants and fellowships, and detailed synthetic procedures and characterization data are available online.
Key Words
1,3-Enynes, Copper-Catalysis
ID: J54-Y2004-350
