A facile and convenient synthesis of the chiral phthalide framework catalyzed by cationic iridium was developed. The method utilized cationic iridium/bisphosphine-catalyzed asymmetric intramolecular carbonyl hydroacylation of 2-keto benzaldehydes to furnish the corresponding optically active phthalide products in good to excellent enantioselectivities (up to 98% ee). The mechanistic studies using a deuterium-labelled substrate suggested that the reaction involved an intramolecular carbonyl insertion mechanism to iridium hydride intermediate. In addition, we investigated the kinetic isotope effect (KIE) of intramolecular hydroacylation with deuterated substrate and determined that the C−H activation step is not included in the turnover-limiting step.
|Number of pages||5|
|Journal||Chemistry - An Asian Journal|
|Publication status||Published - 2020 Jun 17|
- cationic iridium
- C−H activation
ASJC Scopus subject areas
- Organic Chemistry