Direct Construction of Diverse Polyheterocycles Bearing Pyrrolidinediones via Rh(III)‐Catalyzed Cascade C−H Activation/Spirocyclization

Abstract

Rh(III)-catalyzed cascade oxidative annulation of 2-arylquinazolinones with various maleimides to afford spiroisoindoloquinazolinones bearing pyrrolidinediones is described. Sequential ortho CÀ H functionalization and spirocyclization via aza-Michael addition result in the formation of both CÀ C and CÀ N bonds in a single operation. This atom-and step-economic strategy provides an efficient and novel approach for the syntheses of diverse polyheterocycles bearing pyrrolidinediones, starting from 2-heteroarylquinazolinones and 5-arylpyrazolopyrimidinones, in good to excellent yields.

Transition Metal Promoted Cascade Heterocycle Synthesis through C−H Functionalization

“…Lee and co‐workers, in 2019, reported the one‐pot rhodium‐catalyzed C(sp 2 )‐H activation/spirocyclization sequence for the synthesis of quinazolinone nucleus‐based cores . The authors demonstrated that quinazolinones 37 undergo initial C−H functionalization with maleimides 35 followed by spirocyclization by aza‐Michael addition (Scheme ).The desired polyheterocycles 38 were obtained with high yields and broad scope allowing the formation of one C−C and one C−N bond in one‐pot process with high atom economy.…”

Transition metal-catalyzed coupling of heterocyclic alkenesviaC–H functionalization: recent trends and applications

“…Furthermore, the coupling with pyrrolidinediones is studied to produce polyheterocycles (Scheme 86D). 130 This low catalyst loading method is applicable to diverse substrates to give the spiroproducts. The mechanism involves the reversible C-H cleavage (KIE = 2.33), migratory insertion of maleimide, E2-elimination and aza-Michael addition.…”

Rh(III)‐Catalyzed [4+2] Cyclization of 2‐Aryl‐1H‐benzo[d]imidazoles with Maleimides via C‐H Activation

“…[9] In the meantime, Lee group disclosed the Rh(III)-catalyzed tandem cyclization of maleimides with various 2-arylquinazolinones. [10] Fan and co-workers developed an additive-controlled cyclization of maleimides with 2-arylindazoles for the switchable construction of formal [4 + 1]-and dehydrogenated [4 + 2]cyclization products. [11] Very recently, Kumar described a substrate-controlled Rh(III)-catalyzed dehydrogenative cyclization and spirocyclization of 2-arylindoles with maleimides to generate a variety of nitrogen-containing heterocycles.…”

“…[8] For example, Jeganmohan reported an Rh(III)‐catalyzed formal [4+1]‐cyclization of N ‐methoxy benzamides with maleimides via C−H bond activation [9] . In the meantime, Lee group disclosed the Rh(III)‐catalyzed tandem cyclization of maleimides with various 2‐arylquinazolinones [10] . Fan and co‐workers developed an additive‐controlled cyclization of maleimides with 2‐arylindazoles for the switchable construction of formal [4+1]‐ and dehydrogenated [4+2]‐cyclization products [11] .…”