Construction of Polyheterocyclic Skeletons through C−H Bond Activation‐Initiated Cascade Reactions by Using Cyclopropanol as Alkylating Agent as well as Masked Nucleophile and Electrophile

Abstract

AbstractPresented herein is a synthesis of indane fused bicyclic pyrazolidinones based on the reactions of aryl azomethine imines with cyclopropanols. Mechanistically, the formation of product involves Rh(III)‐catalyzed direct aryl C(sp2)−H alkylation of aryl azomethine imine with cyclopropanol through in situ ring‐opening, followed by cascade intramolecular C‐ and N‐nucleophilic addition. In this tandem process, cyclopropanol acts as not only an alkylating agent but also masked nucleophile and electrophile to participate in the construction of both the indane and the bicyclic pyrazolidinone scaffolds. To our knowledge, such a cascade reaction pattern has not been disclosed. In general, this synthetic protocol has advantages such as easily obtainable substrates, valuable products, concise synthetic procedure, unique reaction pathway, and good compatibility with diverse functional groups.