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

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• 作者：Baris Yucel ; ^{yucelbar@itu.edu.tr} ; Bahar Sanli ; Huseyin Soylemez ; Huseyin Akbulut
• 关键词：1 ; 2-Disubstituted ferrocene ; Ferrocene carboxaldehyde ; Ferroceno-pyran ferrocenyl alcohol ; Ferrocenyl alkene
• 刊名：Journal of Organometallic Chemistry
• 出版年：2012
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：1 May, 2012
• 卷：704
• 期：Complete
• 页码：49-64
• 文件大小：930 K

摘要

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聽掳C for different reaction times (between 6 and 26聽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聽掳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聽h) are necessary to drive the reactions to completion. Mechanisms are also suggested for the formation of observed products.