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Synfacts 2011(7): 0760-0760  
DOI: 10.1055/s-0030-1260664
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart ˙ New York

Catalytic Enantioselective Alkynylation of Trifluoromethyl Ketones

Contributor(s): Hisashi Yamamoto, Dmitry L. Usanov
G.-W. Zhang, W. Meng, H. Ma, J. Nie, W.-Q. Zhang, J.-A. Ma*
Tianjin University and Nankai University, Tianjin, P. R. of China
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Publication History

Publication Date:
17 June 2011 (online)

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Significance

Trifluoromethyl ketones represent a class of particularly challenging substrates for the stereoselective addition of alkynes to the carbonyl group; some of the corresponding products possess high importance for the pharmaceutical ­science (for example, see the recent efavirenz synthesis: N. Chinkov, A. Warm, E. M. Carreira Angew. Chem. Int. Ed. 2011, 50, 2957). In this ­paper a titanium-mediated enantioselective addition of zinc alkynylides to trifluoromethyl ketones is reported. Notable, using accessible cinchona alkaloids A and B, both enantiomers of the ­corresponding propargyl alcohols are generally available with good to high yields (up to 98%) and enantioselectivities (up to 94% ee).