Copper Catalyzed sp3 C-H Etherification with Acyl Protected Phenols

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