Redox-neutral C–H annulation strategies for the synthesis of heterocycles via high-valent Cp*Co(iii) catalysis

Abstract

A variety of biologically active molecules, pharmaceuticals, and natural products consist of a nitrogen-containing heterocyclic backbone. Majority of them are isoquinolones, indoles, isoquinolines, etc; thereby the synthesis and derivatization of...

Ru(II)-Catalyzed C(sp2)–H Activation Annulation: Synthesis of Fluorescent Benzoisoquinolonyl Acetate/Peptides from N-Arylamides and Ethyne at Room Temperature

“…The transition metal-catalyzed regioselective C–H activations of core aromatic/aliphatic molecules are extensively reported by installing directing groups . Various transition metal catalyst have been used for the synthesis of isoquinolone derivatives from aryl amide and ethyne molecules via C–H activation annulation. − A fascinating example is the atroposelective synthesis of biaryl by Rh­(III)-catalyzed C–H activation and intermolecular coupling with sterically hindered alkynes . Methoxybenzamide and vinylene carbonate, equivalent to acetylene, have also been utilized for the synthesis of isoquinolone derivatives by Rh­(III)-catalyzed C–H activation annulation at room temperature .…”

Harnessing Vinyl Acetate as an Acetylene Equivalent in Redox-Neutral Cp*Co(III)-Catalyzed C–H Activation/Annulation for the Synthesis of Isoquinolones and Pyridones

“…Recent developments in the area of C–H functionalization have shifted the focus toward the utility of inexpensive and earth-abundant first-row transition metals (e.g., Co, Cu, Fe, Ni, and Mn) in these transformations . In this regard, Cp*Co­(III)-catalysis has seen significant development in the area of C–H functionalization . This is accounted for the low cost, easy preparation, and air stability of Cp*Co­(III) catalysts.…”

“… 9 In this regard, Cp*Co(III)-catalysis has seen significant development in the area of C–H functionalization. 10 This is accounted for the low cost, easy preparation, and air stability of Cp*Co(III) catalysts. Various elegant approaches for the synthesis of isoquinolones were also reported under Cp*Co(III)-catalysis utilizing N -methoxyamide as a substrate, wherein the N–O bond works as an internal oxidant.…”

Co(iii)-catalyzed regioselective benzannulation of substituted pyridones with 1,6-diynes via dual C–H bond activation

“…In this regard, a high-valent cobalt-catalyzed C–H functionalization emerged as an effective strategy, by utilizing an inexpensive and earth-abundant catalyst, along with its high selectivity and specificity in product formation. 16 In this protocol, the cobalt catalyst shows unique reactivity with 1,6-diynes via dual C–H bond functionalization. Hereby, we have synthesized various hetero atom-containing polycyclic quinolinone molecules by utilizing this methodology.…”