、 乙酸酐 在
perchloric acid immobilized on silica gel 作用下,
以
二氯甲烷 为溶剂,
反应 2.0h,
以87%的产率得到2-O-(2-acetoxyisopropyl)-1,3-di-O-acetyl-5-O-benzoyl-β-D-xylofuranoside
参考文献:
名称:
An atom-efficient and powerful method for direct esterification of silyl ethers catalyzed by HClO4–SiO2
摘要:
An efficient and convenient procedure for direct esterification of alkyl and aryl silyl ethers with Ac2O and a catalyst system of perchloric acid immobilized on a silica gel (HClO4 SiO2) has been developed. The silyl protecting groups are directly replaced by acetyls and the protecting groups themselves are transformed into acetates as the sole byproducts, which can be readily recovered and converted back to silylchlorides, the original protecting agents, thus minimizing wastes. (C) 2010 Elsevier Ltd. All rights reserved.
The transformation of acetonides into acetates is frequently required in synthetic chemistry. An efficient procedure for direct conversion of acetonides into acetates in the presence of HClO4-SiO2 under mild conditions was developed. The acetonides of primary hydroxy groups are directly converted to diacetates, and the anomeric acetonides of furanosides are stereoselectively transformed into the corresponding acetyl beta-D-furanosides with a 2-acetoxyisopropyl group. (C) 2009 Elsevier Ltd. All rights reserved.