New application of cross-linked poly(<i>N</i>-bromoacrylamide) and poly(<i>N</i>-bromosuccinimide) as highly efficient and chemoselective heterogeneous polymeric catalysts for deprotection of 1,3-dithianes and 1,3-dithiolanes under mild conditions
作者:Farzaneh Ebrahimzadeh
DOI:10.1080/17415993.2015.1094805
日期:2016.1.2
They were also effective as a reagent in aqueous media. These methods are very simple and the polymer catalysts could be recycled several times. Deprotection of thioacetal and thioketal without enolizable hydrogens proceeded very well to give only the corresponding aldehyde and ketone in high to excellent yield. Nevertheless, in the case of thioketals carrying enolizable hydrogens, deprotection accompanied
摘要 交联聚(N-溴丙烯酰胺)(PNBA)和聚(N-溴代琥珀酰亚胺)作为温和高效的多相聚合物催化剂,用于选择性脱保护 1,3-二噻烷和 1,3-二硫戊烷为其相应的羰基化合物. 它们在水性介质中作为试剂也是有效的。这些方法非常简单,聚合物催化剂可以多次循环使用。没有可烯醇化氢的硫缩醛和硫缩酮的脱保护进行得非常好,仅以高产率至极好的产率得到相应的醛和酮。然而,在带有可烯醇化氢的硫缩酮的情况下,观察到伴随形成少量扩环产物的脱保护。然而,使用 PNBA/H2O 系统,未检测到这些硫醇缩酮与可烯醇化氢的环膨胀。这些方法提供了优势,例如化学选择性、易于制备、简单的后处理、优异的产率和回收催化剂的能力,这使得该方法与其他已知方法相比更有用。图形概要