Pictet-Spenglerreactions of m-tyramine and aldehydes producedtetrahydroisoquinolines in the presence of a catalytic amount of Ca[OCH(CF3)2]2. This reaction occurs with a variety of aryl, heteroaryl, and alkyl aldehydes, producingtetrahydroisoquinolines in high yield and with high regioselectivity. This calcium-promoted Pictet-Spenglerreaction provides a mild alternative to the traditional Bronsted
Catalytic Pictet–Spengler reactions using Yb(OTf)3
作者:Kei Manabe、Daisuke Nobutou、Shū Kobayashi
DOI:10.1016/j.bmc.2005.05.018
日期:2005.9
The catalytic Pictet-Spengler reactions proceeded in high yields with high regioselectivity in the presence of a catalytic amount of Yb(OTf)(3) and a dehydrating agent at room temperature. High regioselectivities were obtained in these reactions, and it is suggested that the reactions proceeded under kinetic control. (c) 2005 Elsevier Ltd. All rights reserved.
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.