Iron-catalyzed cross-dehydrogenative coupling esterification of unactive C(sp3)-H bonds with carboxylic acids for the synthesis of α-acyloxy ethers

J Org Chem. 2014 May 2;79(9):3847-55. doi: 10.1021/jo500192h. Epub 2014 Apr 11.

Abstract

An iron-catalyzed oxidative esterification reaction between unactivated C(sp(3))-H bonds from symmetric and asymmetric ethers and carboxylic acids using di-tert-butyl peroxide (DTBP) as the oxidant via a cross dehydrogenative coupling (CDC) reaction was established, which tolerates a wide range of cyclic ether substrates to react with aromatic acids and phenylacetic acid, providing an efficient method for the preparation of α-acyloxy ethers with good to excellent yields. Intermolecular competing kinetic isotope effect (KIE) experiments were also carried out, which indicate that C(sp(3))-H bond cleavage may be the rate-determining step of this CDC reaction.