preparation of 5-hydroxy-25,26,27,28-tetrapropoxycalix[4]arene has been found. Lithiation of the initial monobromo derivative and subsequent oxidation by oxygen led directly to the proposed calix[4]arenederivative bearing a hydroxy group on the upper rim. The product has been used for the preparation of novel molecularreceptors based on multiple calix[4]arenes.
Highly enantioselective aldol reactions catalyzed by reusable upper rim-functionalized calix[4]arene-based l -proline organocatalyst in aqueous conditions
作者:Zheng-Yi Li、Yuan Chen、Chong-Qian Zheng、Yue Yin、Liang Wang、Xiao-Qiang Sun
DOI:10.1016/j.tet.2016.11.052
日期:2017.1
l-Proline derivatives have been synthesized and employed for the enantioselective aldol reactions between cyclic ketones and aromatic aldehydes in the presence of water. Good to excellent yields (up to 96%), enantioselectivities (up to 99% ee), as well as diastereoselectivities (up to 99:1 dr) were obtained under the optimal reaction conditions. Detailed experiments clearly showed that the hydrophobic
A calix[4]arene based boronic acid catalyst for amide bond formation: proof of principle study
作者:Asslly Tafara Mafaune、Gareth E. Arnott
DOI:10.24820/ark.5550190.p010.492
日期:——
A calix[4]areneboronicacid was synthesized and tested for catalysis in amideformation. The results were positive and paved the way for future designs, even though protodeboronation was observed under the conditions employed.