Calcium-Promoted Pictet-Spengler Reactions of Ketones and Aldehydes

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• 作者：Matthew J. Vanden Eynden ; Kamala Kunchithapatham ; James P. Stambuli
• 刊名：Journal of Organic Chemistry
• 出版年：2010
• 出版时间：December 17, 2010
• 年：2010
• 卷：75
• 期：24
• 页码：8542-8549
• 全文大小：991K
• 年卷期：v.75,no.24(December 17, 2010)
• ISSN：1520-6904

文摘

Calcium bis-1,1,1,3,3,3-hexafluoroisopropoxide is shown to be an effective catalyst for Pictet−Spengler reactions of 3-hydroxyphenethylamine and 3-hydroxy-4-methoxyphenethylamine with various aldehydes and ketones. Previous Lewis acid catalyzed Pictet−Spengler reactions of unactivated ketones typically require two separate reactions (imine formation, cyclization) to obtain the same results. The reactions described within directly provide 1,1′-disubstituted tetrahydroisoquinolines from the corresponding amine and ketone. These rare examples of Pictet−Spengler reactions of unactivated ketones demonstrate the unique nature of calcium as a Lewis acid catalyst.