A Convenient Preparation of Xanthene Dyes

A facile synthetic route utilizing readily available reagents affords a series of regioisomerically
pure xanthene dye derivatives. Advantages include relatively mild conditions and good to excellent
yields. Nonpolar, highly crystalline intermediates are isolable by standard chromatographic
techniques. The intermediates are in the requisite xanthene oxidation state, thus avoiding the
need for relatively inefficient oxidation chemistry and/or harsh conditions. During the course of
this work, a new boron-mediated 1,2-aryl migration reaction was discovered.

本研究采用易得试剂构建了一条简便合成路线，可制备得到一系列区域异构体纯的呫吨（xanthene）染料衍生物。该路线具备反应条件相对温和、产物收率良好至优异的优势。其非极性高结晶中间体可通过标准色谱技术分离，且该中间体处于目标呫吨氧化态，因此无需使用效率较低的氧化反应或苛刻反应条件。本研究过程中还发现了一种新型硼介导的1,2-芳基迁移反应。