A Hg(OTf)₂-Catalyzed Enolate Umpolung Reaction Enables the Synthesis of Coumaran-3-ones and Indolin-3-ones

Abstract

The potential of mercury catalysis has been extended to the arena of enolate umpolung reactions for the first time by the generation of enolonium species via Hg(OTf) 2 -catalyzed N-oxide addition to alkynes. The enolonium species formed can undergo intramolecular nucleophilic attack by hydroxyl or amino groups, leading to the synthesis of various coumaran-3-ones and indolin-3-ones.

Structure-based optimization of type III indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors

“…2-Ethynyl-4-methylphenol ( 18g ) 104 : Synthesised from 2-iodo-4-methylphenol (468 mg, 2 mmol) according to the general procedure ( I ) to afford the title compound as an oil (211 mg) in 80% yield. 1 H NMR (400 MHz, CDCl 3 ) δ 7.20 (d, J = 2.2 Hz, 1H), 7.10 (dd, J = 8.4, 2.2 Hz, 1H), 6.87 (d, J = 8.4 Hz, 1H), 5.65 (s, 1H), 3.46 (s, 1H), 2.27 (s, 3H).…”

2‐(Alkynyl)anilines and Derivatives — Versatile Reagents for Heterocyclic Synthesis

“…The transformation of 2‐alkynylanilines into 3‐oxindoles was realized under mercury triflate catalysis [110] . Chlorine substituted pyridine N ‐oxide served as a source of oxygen.…”

Annulation of 2‐Alkynylanilines: The Versatile Chemical Compounds

“…The advancement of this reaction relies on the formation of enolonium species 15 and intramolecular S N 2′ reaction (Scheme 5). [47] This reaction was also catalyzed by gold catalytic system [48] …”

“…The advancement of this reaction relies on the formation of enolonium species 15 and intramolecular S N 2' reaction (Scheme 5). [47] This reaction was also catalyzed by gold catalytic system. [48] 2-(Inden-2-yl)-indole-3-one compounds 18 were designed and synthesized by the reaction of 8 with dihydroindenone 17 in the presence of FeCl 3 as catalyst (Scheme 6).…”