Palladium-catalyzed reaction of 2-iodoferrocenyl alcohols with internal alkynes: Synthesis of functionally 1,2-disubstituted ferrocenes and ferroceno-pyrans


Yücel B. , SANLI B., SOYLEMEZ H., AKBULUT H.

JOURNAL OF ORGANOMETALLIC CHEMISTRY, vol.704, pp.49-64, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 704
  • Publication Date: 2012
  • Doi Number: 10.1016/j.jorganchem.2012.01.007
  • Title of Journal : JOURNAL OF ORGANOMETALLIC CHEMISTRY
  • Page Numbers: pp.49-64

Abstract

The reaction of racemic (2-iodoferrocenyl)methanol with internal alkynes in the presence of (dppf)PdCl2 and i-Pr2NH produces alkenyl-substituted ferrocene carboxaldehydes in moderate yields. All reactions are carried out at 100 or 120 degrees C for different reaction times (between 6 and 26 h) in a screw-cap Pyrex bottle. The scope and limitations of this reaction are studied by employing variously substituted 11 internal alkynes. The reactions are regioselective with alkynes having a sterically crowded substituent such as t-butyl and trimethylsilyl groups. Moreover, racemic 1-(2-iodoferrocenyl) ethanol derivatives are synthesized as two diastereomers. Both diastereomers are reacted with internal alkynes in the presence of (dppf)PdCl2 and i-Pr2NH at 120 degrees C to afford alkenyl-substituted acetylferrocenes and ferroceno-pyrans in moderate to good yields. According to the alkyne employed, different reaction times (between 6 and 55 h) are necessary to drive the reactions to completion. Mechanisms are also suggested for the formation of observed products. (C) 2012 Elsevier B.V. All rights reserved.