1,3-Dienones and 2H-Pyran-2-ones from Soft 伪-Vinyl Enolization of 尾-Chlorovinyl Ketones: Defined Roles of Br枚nsted and Lewis Base

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• 作者：Hun Young Kim ; Kyungsoo Oh
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：December 18, 2015
• 年：2015
• 卷：17
• 期：24
• 页码：6254-6257
• 全文大小：339K
• ISSN：1523-7052

文摘

The eliminative reaction pathways of (E)-尾-chlorovinyl ketones were investigated in the presence of both Br枚nsted and Lewis bases. The Br枚nsted base, Et₃N, effected the soft 伪-vinyl enolization of (E)-尾-chlorovinyl ketones to [3]cumulenol intermediates; in turn, a catalytic amount of Lewis base, PPh₃, initiated isomerization to provide 1,3-dienones in high yields. The introduction of a carbon-based nucleophile into the reaction mixture provided the highly efficient synthetic route to 2H-pyran-2-ones in one pot, where the carbon-based nucleophile generated by an extra equivalent of Br枚nsted base, Et₃N, attacked the electrophilic [3]cumulenol intermediates to initiate cyclization to give 2H-pyran-2-ones.