Iridium-catalyzed [4 + 2] annulation of 1-arylindazolones with α-diazo carbonyl compounds: access to indazolone-fused cinnolines

Abstract

An Ir-catalyzed tandem strategy for the synthesis of indazolone-fused cinnolines by [4 + 2] annulation of 1-arylindazolones with α-diazo carbonyl compounds.

Recent advances in transition-metal-catalyzed carbene insertion to C–H bonds

“…294 With dimethyl (1-diazo-2oxopropyl)-phosphonate as the carbene source compound 3indolylphosphonates were accessed in 59-75% yields. Other directing groups such as pyridyl, 295 ketone, 296 phosphine oxide, 297 and pyrazolyl 298 were also applied in iridiumcatalyzed intermolecular aryl C(sp 2 )-H functionalization by carbene insertion with diazo compounds. Under Ir(III) catalysis 2-(arylamino)pyridines (191) reacted with acceptor/acceptor diazo compound 260 in the presence of LiOAc in CF 3 CH 2 OH (TFE) to afford oxindole derivatives 261 in up to 72% yields (eqn ( 64)).…”

Recent advances in the synthesis of bridgehead (or ring-junction) nitrogen heterocycles via transition metal-catalyzed C–H bond activation and functionalization

“…In 2018, Sakhuja et al reported an Ir-promoted annulation of 1-arylindazolones with α-diazo carbonyl compounds, providing indazolone-fused cinnolines 172 in good to excellent yields (Scheme 41). 70 Obviously, the Ir(I) species facilitates the N-H oxidative addition of 1-arylindazolone and affords the five-membered Ir(III) intermediate 171 which reacts with α-diazo carbonyl compounds, to generate the final desired product.…”

Indazolone‐Assisted Sequential ortho‐Alkenylation‐Oxidative Aza‐Michael Addition of 1‐Arylindazolone Using Acrylates Under Ru(II) Catalysis

“…In this realm, Perumal et al ., Xu et al . and our group have achieved the synthesis of indazolone‐fused cinnolines by the coupling of 1‐arylindazolones/2‐arylindazolones with alkynes and α ‐diazocarbonyls using Rh(III), Ir(I), Ru(III) catalysis.…”

“…Anticipating the potential directing grouping ability of indazolone moiety and strong coordinating ability of acrylates, we envisioned that 1‐arylindazolones could be selectively functionalized using acrylates under metal‐catalyzed conditions in a one‐pot manner. As a continuation of our interest in C−H bond activation, we herein disclose an efficient Ru(II)‐catalyzed strategy for the coupling of 1‐arylindazolones with acrylates to furnish indazolo[1,2‐ a ]indazolylidenes (Scheme d).…”