Rh(III)-Catalyzed Oxidative Annulation of Isoquinolones with Diazoketoesters Featuring an in Situ Deacylation: Synthesis of Isoindoloisoquinolones and Their Transformation to Rosettacin Analogues

A novel and practical procedure for the preparation of isoindolo­[2,1-b]­isoquinoline-7-carboxylate derivatives through a Rh­(III)-catalyzed oxidative [4 + 1] cycloaddition of isoquinolones with diazoketoesters followed by an in situ deacylation reaction is disclosed. Intriguingly, the title compounds could be easily converted into isoindolo­[2,1-b]­isoquinolin-5­(7H)-ones via de-esterification, which are rosettacin analogues and frequently found in various natural alkaloids and synthetic drug molecules.