Corin Schowalter and Robert Strongin, Chemistry

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. Non-polar, 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. The methods described herein are now being utilized in our lab towards the synthesis of new naphthofluorescein dye architectures currently unattainable via other methodology. During the course of this work, a new boron–mediated 1,2-aryl migration reaction was discovered.