Pd(II)-Catalyzed ortho- or meta-C–H Olefination of Phenol Derivatives
journal contributionposted on 22.05.2013, 00:00 by Hui-Xiong Dai, Gang Li, Xing-Guo Zhang, Antonia F. Stepan, Jin-Quan Yu
A combination of weakly coordinating auxiliaries and ligand acceleration allows for the development of both ortho- and meta-selective C–H olefination of phenol derivatives. These reactions demonstrate the feasibility of directing C–H functionalizations when functional groups are distal to target C–H bonds. The meta-C–H functionalization of electron-rich phenol derivatives is unprecedented and orthogonal to previous electrophilic substitution of phenols in terms of regioselectivity. These methods are also applied to functionalize α-phenoxyacetic acids, a fibrate class of drug scaffolds.