Palladium-catalyzed ortho-acylation of 2-arylbenzoxazoles

An efficient and facile catalytic protocol for benzoxazole-directed ortho-acylation of 2-arylbenzoxazoles has been described using aldehydes as the easily accessible acyl source. This catalytic system was performed in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant in chlorobenzene, affording the acylated 2-arylbenzoxazoles in moderate to good yields. The acylation exhibited high regioselectivity for the substrates containing a meta-substituent in the benzene ring and typically occurred at the less sterically hindered ortho-C-H bond of the directing group. (C) 2012 Elsevier Ltd. All rights reserved.