Indium-Catalyzed 2-Alkenylation of 1,3-Dicarbonyl Compounds with Unactivated Alkynes

Kohei Endo, Takuji Hatakeyama,† Masaharu Nakamura,*† and Eiichi Nakamura*‡
Contribution from the Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
J. Am. Chem. Soc., 2007, 129 (16), pp 5264–5271
DOI: 10.1021/ja0702014
Publication Date (Web): March 28, 2007
Copyright © 2007 American Chemical Society
†

 Present address:  International Research Center for Elements Science, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.

,
*

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

,
‡

 ERATO, Japan Science and Technology Agency.

, nakamura@chem.s.u-tokyo.ac.jp

Abstract

Abstract Image

1,3-Dicarbonyl compounds add to unactivated alkynes in the presence of a catalytic amount of indium(III) trifluoromethanesulfonate in high to excellent yield to give 2-alkenylated 1,3-dicarbonyl compounds with exclusive regioselectivity as to the position of C−C bond formation on the acetylene moiety. In most of the cases, the reaction requires less than 1-mol % loading of the catalyst and does not require solvent. The reaction tolerates a wide variety of functional groups including ester, ether, allylic halide, furan, thiophene, and protected amine. Experimental and theoretical studies suggested that the reaction proceeds via a concerted carbometalation reaction of an indium(III) enolate with the acetylene, where indium−acetylene interaction is important.

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History

  • Published In Issue April 25, 2007
  • Received January 10, 2007

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