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Synfacts 2006(1): 0044-0044
DOI: 10.1055/s-2005-921677
DOI: 10.1055/s-2005-921677
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York
Rh-Catalyzed Enantioselective [4+2] Cyclization of 4-Alkynals and Acrylamides
K. Tanaka*, Y. Hagiwara, K. Noguchi
Tokyo University of Agriculture and Technology, Japan
Further Information
Publication History
Publication Date:
16 December 2005 (online)
![](https://www.thieme-connect.de/media/synfacts/200601/lookinside/thumbnails/10.1055-s-2005-921677-1.jpg)
Significance
A Rh-catalyzed intermolecular [4+2] cycloaddition of 4-alkynal and N,N-dialkylacrylamides afforded cyclohexanones in moderate to excellent yields and excellent ee’s. It was found that the cationic rhodium precursor and bidentate (R,R)-walphos ligand gave the optimal results in both yield and ee. A good range of substituents on the alkynal was compatible. In general, reactions with 2-alkynylbenzaldehydes are easier than those with linear alkynals, presumably due to the limited conformational options in the substrate.