Assembly of Conjugated Enynes and Substituted Indoles via CuI/Amino Acid-Catalyzed Coupling of 1-Alkynes with Vinyl Iodides and 2-Bromotrifluoroacetanilides

Feng Liu and Dawei Ma*
State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
J. Org. Chem., 2007, 72 (13), pp 4844–4850
DOI: 10.1021/jo070547x
Publication Date (Web): May 27, 2007
Copyright © 2007 American Chemical Society
*

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

, madw@mail.sioc.ac.cn

Abstract

Abstract Image

Cross-coupling of 1-alkynes with vinyl iodides occurs at 80 °C in dioxane catalyzed by CuI/N,N-dimethylglycine to afford conjugated enynes in good to excellent yields. Heating a mixture of 2-bromotrifluoroacetanilide, 1-alkyne, 2 mol % of CuI, 6 mol % of l-proline, and K2CO3 in DMF at 80 °C leads to the formation of the corresponding indole. This conversion involves a CuI/l-proline-catalyzed coupling between aryl bromide and the 1-alkyne followed by a CuI-mediated cyclization process. An ortho-substituent effect directed by NHCOCF3 enables the reaction to proceed under these mild conditions. Both aryl acetylenes and O-protected propargyl alcohol can be applied, leading to 5-, 6-, or 7-substituted 2-aryl and protected 2-hydroxymethyl indoles in good yields. With simple aliphatic alkynes, however, lower yields were observed.

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History

  • Published In Issue June 22, 2007
  • Received March 16, 2007

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