Zinc chloride homogeneous catalysis in the tritylation of hydroxyl- and amide-bearing molecules
作者:Maurizio Maltese、Maria Cecilia Vergari、Maria Pia Donzello
DOI:10.1016/j.tetlet.2010.11.095
日期:2011.1
A tritylation protocol based on the transfer of the triphenylmethylcarbenium ion from trityl acetate to substrates having hydroxyls, in the presence of catalytic amounts of ZnCl2, is described. The advantages of this method are broad scope, mild conditions, and easy handling. The comparison with the procedure based on the use of equimolar mixture of TrCl and ZnCl2 in the presence of TEA shows that
描述了在催化量的ZnCl 2存在下基于三苯甲基碳鎓离子从乙酸三苯甲基酯转移至具有羟基的底物的三苯甲基化方案。该方法的优点是适用范围广,条件温和且易于操作。与基于在TEA存在下使用TrCl和ZnCl 2等摩尔混合物的方法的比较表明,获得了可比较的结果。但是,只有这种方法才能抑制仲醇或苄醇的反应,例如氧化或对称醚的形成。两种方法都成功地扩展到简单和取代的酰胺。不管其在乙腈中的溶解度如何,即使是天冬酰胺也可以直接在其酰胺基上三苯甲基化。