Formal aromatic C-H insertion for stereoselective isoquinolinone synthesis and studies on mechanistic insights into the C-C bond formation.

Chan Pil Park, Advait Nagle, Cheol Hwan Yoon, Chiliu Chen, Kyung Woon Jung

Index: J. Org. Chem. 74(16) , 6231-6, (2009)

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Abstract

Formal aromatic C-H insertion of rhodium(II) carbenoid was intensively investigated to develop a new methodology and probe its mechanism. Contrasting with the previously proposed direct C-H insertion, the mechanism was revealed to be electrophilic aromatic substitution, which was supported by substituent effects on the aromatic ring and a secondary deuterium kinetic isotope effect. Various isoquinolinones were synthesized intramolecularly via six-membered ring formation with high regio- and diastereoselectivity, while averting the common Buchner-type reaction. Intermolecularly, dirhodium catalyzed formal aromatic C-H insertion on electron-rich aromatics was also achieved.