Ir(III)-Catalyzed Dual C–H Activation of 2-Aryl Phthalazinediones and 3-Aryl-2H-benzo[e][1,2,4]thiadiazine-1,1-dioxides for the Construction of Spiro-Fused Cyclic Frameworks

Abstract

An Ir(III)-catalyzed double C−H activation strategy has been developed for the synthesis of highly rigid spiro frameworks by means of ortho-functionalization of 2-aryl phthalazinediones and 2,3-diphenylcycloprop-2-en-1-ones using the Ir(III)/AgSbF 6 catalytic system. Similarly, 3-aryl-2H-benzo[e][1,2,4]thiadiazine-1,1-dioxides undergo smooth cyclization with 2,3diphenylcycloprop-2-en-1-ones to afford a diverse range of spiro compounds in good yields with excellent selectivity. Additionally, 2arylindazoles provide the corresponding chalcone derivatives under similar reaction conditions.

Cascade [4 + 1] Annulation through Activation of the C(sp2)–H Bond Enabling Benzothiadiazinoisoindolcarboxylate, Benzothiadiazinoisoindole, and Benzothiadiazinoisoindolepyrrolidinedione as Hybrid Spiro-Heterocyclic Frameworks

“…Recently, Parthasarathy et al has developed Rh­(III)-catalyzed Heck coupling followed by annulation protocol to construct benzothiadiazinoisoquinoline 6,6-dioxides and benzothiadiazinoisoindole 5,5-dioxides scaffolds proficiently . Apart from that, Subba Reddy et al have strategized an Ir­(III) catalyst-mediated dual C–H activation on benzothiadiazine dioxides in conjunction with diphenylcyclopropenones to produce spirocyclic heteroarenes . Concentrating on the previous methodologies and potent features of spirocyclic hybrid heterocycles, herein, we wish to report a robust Rh­(III) metal-catalyzed concurrent ortho -sp 2 C–H bond activation and aza-Michael cyclization of dihydrobenzothiadiazine dioxides along with the coupling conjugates maleimide, dialkyl maleate, and styrene to fabricate spirocyclic benzothiadiazinoisoindolepyrrolidinedione-5,5-dioxide, benzothiadiazinoisoindolcarboxylate-5,5-dioxide, or benzothiadiazinoisoindole-5,5-dioxide hybrid heterocyclic moieties, respectively (Scheme ).…”