Copper catalyzed coupling of protecting group free and sterically hindered 2-bromobenzyl tertiary alcohols with phenols and anilines: facile synthesis of xanthenes and dihydroacridines

A simple and efficient method for the synthesis of xanthenes and dihydroacridines containing a quaternary carbon atom at the 9th-position, is presented. Significantly, the protocol facilitated the smooth participation of sterically hindered and protecting group free 2-bromobenzyl tertiary alcohols in cross coupling reactions with phenols and anilines, under copper-catalysis. The Lewis acid mediated intramolecular C-C bond formation enabled the formation of a quaternary carbon atom at the 9th-position. Remarkably, this two-step protocol required a single column purification technique.