Total Synthesis of Spirobenzylisoquinoline Alkaloids. Part III (±)-Ochrobirine
作者:Stewart McLean、John Whelan
DOI:10.1139/v73-368
日期:1973.8.1
The route to spirobenzylisoquinoline alkaloids through a Pictet–Spengler cyclization of a suitable 1,2-indanedione has been modified, by the introduction of a 3-bromo substituent into the indanedione, with a view to providing a general synthesis of spirobenzylisoquinoline alkaloids bearing two oxygen functions on ring C. A highly stereoselective synthesis of (±)-ochrobirine has been achieved.
通过适当的 1,2-茚二酮的 Pictet-Spengler 环化反应制备螺苄基异喹啉生物碱的路线已被修改,将 3-溴取代基引入茚满二酮,以期提供带有两个氧的螺苄基异喹啉生物碱的一般合成环 C 上的功能。已经实现了 (±)-ochrobirine 的高度立体选择性合成。
Calcium-Promoted Pictet-Spengler Reactions of Ketones and Aldehydes
作者:Matthew J. Vanden Eynden、Kamala Kunchithapatham、James P. Stambuli
DOI:10.1021/jo1019283
日期:2010.12.17
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.