Lewis acid-catalyzed claisen rearrangement in the preparation of chiral products
申请人:The Regents of the University of California
公开号:US06359174B1
公开(公告)日:2002-03-19
A novel Claisen rearrangement reaction is provided. An allylic reactant such as an allylic amine, an allylic ether or an allylic thioether is reacted with an acid chloride in the presence of a Lewis acid catalyst composition composed of a Lewis acid and a base selected from the group consisting of tertiary amines and non-nitrogenous bases. The stereochemistry of the reaction product is readily controlled by the positioning and size of substituents on the allylic reactant. The reaction may be carried out on a solid support, i.e., on the surface of a substrate suitable for conducting solid phase chemical reactions.
Using NMR to determine the relative stereochemistry of 7,7-diaryl-8,8′-dimethylbutan-1-ol lignans
作者:Samuel J. Davidson、Claire E. Rye、David Barker
DOI:10.1016/j.phytol.2015.09.014
日期:2015.12
Due to their linear, freely rotatable, structure many natural 7,7-diaryl-8,8'-dimethylbutan-7'-ol lignans are reported without any stereochemical assignment. Analysis of synthetic 8,8'-dimethylbutanol lignans and analogues reveals significant differences between the NMR data of syn-and anti-isomers. This information was then used to determine the relative stereochemistry of the C-8 and C-8' methyl groups in previously undefined natural products. (C) 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
US6359174B1
申请人:——
公开号:US6359174B1
公开(公告)日:2002-03-19
An acyl-Claisen/Paal-Knorr approach to fully substituted pyrroles
作者:Nora Dittrich、Eun-Kyung Jung、Samuel J. Davidson、David Barker
DOI:10.1016/j.tet.2016.06.049
日期:2016.8
The synthesis of fully substituted pyrroles using the Paal-Knorr reaction on acyl-Claisen derived 2,3-syn-disubstituted-1,4-diketones is reported. The use of the acyl-Claisen rearrangement allows the synthesis of wide variety of syn-substituted 1,4-diketones which are shown to be better substrates for pyrrole condensation than their corresponding anti isomers. When the reaction was performed open to