Palladium-catalyzed ortho-acylation of 2-arylbenzoxazoles and 2-arylbenzothiazoles using arylmethyl alcohols as the acyl source
A facile and efficient way for the synthesis of the acylated 2-arylbenzoxazoles and 2-arylbenzothiazoles by heterocycle-directed ortho-acylation was developed. This reaction was performed in chlorobenzene, using arylmethyl alcohols and tert-butyl hydroperoxide (TBHP) as the easily accessible acyl source and the oxidant, respectively, affording the desired products in moderate to good yields.
Zhang, Qian,Yang, Fan,Wu, Yangjie
supporting information
p. 4908 - 4914
(2013/06/26)
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.