Benzimidates as gem-Diamidation and Amidoindolyzation Cascade Synthons with a Hydrated Ni^II Catalyst

Abstract

We contributed a new benzimidate chemistry through moisture-insensitive NiII/NiII-FeIII combo-catalysis for a simultaneous 2–3 bond-forming gem-diamidation and amidoindolyzation cascade reaction to construct symmetrical and unsymmetrical gem-(arylmethylene)­amides and indolo­(arylmethylene)­amides, using emerging benzimidate synthons. The operational simplicity, mild nature, generality, and robustness of the strategy were validated through syntheses of a wide range of new molecules, labile sugar-based chiral compounds, and pharmaceuticals with high yields under the same reaction conditions.

Applications of Ethynylanilines as Substrates for Construction of Indoles and Indole‐Substituted Derivatives

“…also disclosed an elegant one pot synthesis of indole derivatives 92 (Scheme 30). [51] In this reaction optimized conditions disclosed that the reaction gives excellent yields under 2 mol% of Pd (II) catalyst and potassium carbonate as base in DMSO solvent at 90 °C temperature. Various diversely substituted terminal alkynes were demonstrated under this catalytic process which afforded good to excellent yields of the desired indole derivative 92 .…”

“…In the year 2020 Rajesh nandi et al [51] have described Ni II / Ni II -Fe II catalysed formation of Indolo (arylmethylene)-amides 120 (Scheme 41) via gem-diamidation and amidoindolyzation cascade reaction from emerging benzimidate synthons 118. [61] The amidoindolyzation is versatile reaction and it is proved by in situ annulation of 2-alkynyl anilines 119 for the formation of indolyl benzamides 120.…”

“…In the year 2020 Rajesh nandi et al [51] . have described Ni II /Ni II ‐Fe II catalysed formation of Indolo (arylmethylene)‐amides 120 (Scheme 41) via gem‐diamidation and amidoindolyzation cascade reaction from emerging benzimidate synthons 118 [61] .…”

N,N‐Diacylaminals as Emerging Tools in Synthesis: From Peptidomimetics to Asymmetric Catalysis

“…More recently, Ghosh, Maiti, and co‐workers reported the direct synthesis of dissymmetric gem ‐bisamides through cross‐coupling between differently substituted benzimidates (Scheme 5). [31] The efficiency of the moisture‐insensitive Ni II /Ni II ‐Fe III combo‐catalyst was confirmed by the construction of chiral bisamides in high yield and negligible amounts of self‐coupled adducts (<5 %).…”

Nickel‐Catalyzed Cascade Reactions

“…Maiti group constructed multiple new C−C/C−N/C−O bonds using cascade coupling reaction of benzimidates which was catalyzed by air impassive Ni(II)/Ni(II)‐Fe(III) combo catalysts [46] . With the assistance of gem ‐diamidation and amidoindolyzation, benzimidate 76 easily formed symmetrical 78 and unsymmetrical gem ‐(arylmethylene)amides 79 and indolo(arylmethylene)‐amides 82 in presence of 10 mol% Ni(OAc) 2 .4H 2 O catalyst in toluene under refluxing condition for 4–9 h furnishing 70–85 % yield of desired products (Scheme 22).…”