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Synfacts 2006(12): 1258-1258
DOI: 10.1055/s-2006-955633
DOI: 10.1055/s-2006-955633
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York
Asymmetric Addition of in situ Formed Alkynylzincs to Ketones
G. Lu, X. Li, Y.-M. Li, F. Y. Kwong, A. S. C. Chan*
The Hong Kong Polytechnic University and Sun Yat Sen University, Guangzhou, P. R. of China
Further Information
Publication History
Publication Date:
22 November 2006 (online)
Significance
Aromatic and aliphatic ketones can be enantioselectively converted into chiral tertiary propargylic alcohols via addition of terminal alkynes in the presence of a Cu(OTf)2/camphorsulfonamide catalyst and ZnMe2. Enantiomeric excesses were generally good to excellent for the reaction of aromatic ketones with phenylacetylene, whereas sterically hindered ketones and poorly nucleophilic alkynes afforded lower yields and/or ee values. The reaction was also extended to a selective 1,2-addition of phenylacetylene to an α,β-unsaturated ketone, contrasting with the traditional regioselectivity of Cu-catalyzed processes.