A substituted optically active spiropyran with a tolan group in the 6'-position is described. Both the parent spiropyran and its derivative were separated by chiral HPLC and characterized by CD spectroscopy. There is a 'diastereomeric switch' at temperatures below -30 degrees C,but the compound does not show liquid crystalline properties. (C) 1999 Elsevier Science Ltd. All rights reserved.
A substituted optically active spiropyran with a tolan group in the 6'-position is described. Both the parent spiropyran and its derivative were separated by chiral HPLC and characterized by CD spectroscopy. There is a 'diastereomeric switch' at temperatures below -30 degrees C,but the compound does not show liquid crystalline properties. (C) 1999 Elsevier Science Ltd. All rights reserved.
The Thiolate-Catalyzed Intermolecular Crossed Tishchenko Reaction: Highly Chemoselective Coupling of Two Different Aromatic Aldehydes
作者:Simon P. Curran、Stephen J. Connon
DOI:10.1002/anie.201206343
日期:2012.10.22
Crossed products: Ortho‐substituted benzaldehydes react with other aromaticaldehydes in a highly selective, atom‐economical Tishchenko disproportionation (see scheme) in the presence of a readily prepared, inexpensive thiolate‐based catalyst. The methodology is of exceptionally wide scope and exhibits a high functional‐group tolerance.