Copper Catalyzed sp C-H Etherification with Acyl Protected Phenols.

A variety of acyl protected phenols AcOAr participate in sp C-H etherification of substrates R-H to give alkyl aryl ethers R-OAr employing BuOOBu as oxidant with copper(I) β-diketiminato catalysts [Cu]. Although 1°, 2°, and 3° C-H bonds may be functionalized, selectivity studies reveal a preference for the construction of hindered, 3° C-OAr bonds. Mechanistic studies indicate that β-diketiminato copper(II) phenolates [Cu]-OAr play a key role in this C-O bond forming reaction, formed via transesterification of AcOAr with [Cu]-OBu intermediates generated upon reaction of [Cu] with BuOOBu.