Synthesis of Cinnolines via Rh(III)‐Catalyzed Annulation of N‐Aryl Heterocycles with Vinylene Carbonate

Abstract

The Rh(III)‐catalyzed C−H annulation reactions of N‐aryl indazolones or N‐aryl phthalazinones with a vinylene carbonate is described herein. This transformation provides the rapid access to indazolocinnolines and phthalazinocinnolines as important assets towards the development of novel bioactive compounds. Intriguingly, a vinylene carbonate acts as a vinyl transfer agent to enable the [4+2] annulation reaction. This method is characterized by its simplicity, mild reaction conditions, and broad functional group tolerance.

Ruthenium‐catalyzed C−H Functionalization/Annulation ofN‐Aryl Indazoles/Phthalazines with Sulfoxonium Ylides to access Tetracyclic‐fused Cinnolines

“…Some of those compounds exhibit prominent fluorescence properties and could be used for cell imaging due to their excellent biocompatibility and pronounced intracellular imaging characteristics [16] . Very recently, Kim described a Rh‐catalyzed C−H annulation of N ‐aryl indazolones with a vinylene carbonate for the construction of indazolocinnolines (Scheme 1d) [18] . Sakhuja developed the annulation of 1‐arylindazolones with allenoates to access cinnoline‐fused indazolones catalyzed by palladium (Scheme 1e) [19] .…”

“…[16] Very recently, Kim described a Rhcatalyzed CÀ H annulation of N-aryl indazolones with a vinylene carbonate for the construction of indazolocinnolines (Scheme 1d). [18] Sakhuja developed the annulation of 1-arylindazolones with allenoates to access cinnoline-fused indazolones catalyzed by palladium (Scheme 1e). [19] The CÀ H functionalization/annulation of 1-arylindazolones can also deliver indolo [1,2a]quinazolinones and indazolo [1,2-a]indazolones.…”

K2CO3-Promoted Formal [3+3]-Cycloaddition of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Knoevenagel Adducts

“…Therefore, the exploration of practical and efficient methods for the synthesis of dinitrogen-fused heterocycles has attracted extensive attention in the field of organic chemistry and pharmacology. Various methods for the construction of N , N -bicyclic pyridazinylpyrazolidinone skeletons have been reported, including the double acylation of pyrazolidine [ 2 ]; the double alkylation of pyrazolidinone [ 4 ] and indazole [ 6 ]; the annulation by Rh-catalyzed C-H activation [ 7 , 8 ]; Rh-catalyzed [4+1] cyclization of N -arylphthalazine-1,4-dione with 2-diazo carbonyl compounds [ 9 ] or vinylene carbonate [ 10 ]; and the cycloaddition of 1,3-dipolar azomethine imines with various partners [ 11 , 12 , 13 ]. There is no doubt that the [3+3]-cycloaddition of azomethine imines with various dipolarophile precursors is one of the most popular methods in various protocols ( Scheme 1 ).…”

Synthesis of Succinimide-Linked Indazol-3-ols Derived from Maleimides under Rh(III) Catalysis

“… 8 To this end, the transition-metal-catalyzed C–H modification of N -aryl indazol-3-ones with α-diazo carbonyls, alkynes, acrylates, and nitroalkenes has been explored. 9 Driven by our efforts toward the direct integration of two bioactive scaffolds via catalytic C–H functionalization, 10 we herein describe the Rh(III)-catalyzed 1,4-addition of maleimides with N -aryl indazolols as tautomers of N -aryl indazolones, which rapid assembles succinimide-containing indazol-3-ols. The gram-scale experiments and synthetic transformations illustrate the practicality of the current methodology.…”

“…Indazolones and their analogous have attracted great attention by virtue of their biological applications as anticancer, anti-inflammatory, analgesic, antipsychotic, antiviral, and antihyperlipidemic agents . To this end, the transition-metal-catalyzed C–H modification of N -aryl indazol-3-ones with α-diazo carbonyls, alkynes, acrylates, and nitroalkenes has been explored . Driven by our efforts toward the direct integration of two bioactive scaffolds via catalytic C–H functionalization, we herein describe the Rh­(III)-catalyzed 1,4-addition of maleimides with N -aryl indazolols as tautomers of N -aryl indazolones, which rapid assembles succinimide-containing indazol-3-ols.…”