Pd(II)-Catalyzed meta-C–H Olefination, Arylation, and Acetoxylation of Indolines Using a U-Shaped Template
摘要:
meta-C-H olefination, arylation, and acetoxylation of indolines have been developed using nitrile-containing templates. The combination of a monoprotected amino acid ligand and the nitrile template attached at the indolinyl nitrogen via a sulfonamide linkage is crucial for the meta-selective C-H fiunctionalization of electron-rich indolines that are otherwise highly reactive toward electrophilic palladation at the para-positions. A wide range of synthetically important and advanced indoline analogues are selectively functionalized at the meta-positions.
A single and simple ortho‐sulfonyl benzonitrile template was developed to achieve remoteC−H olefination of six different classes of N‐heterocycles. We demonstrate that, by varying precatalysts and conditions, the same template can be applied to the remoteC−Hactivation of six structurally distinct heterocyclic scaffolds, and the site‐selectivity can be predicted based on distance and geometry. Furthermore