Multi-component heteroarene couplings via polarity-reversed radical cascades

Abstract

A unified strategy enables multi-component radical addition cascades to couple alkenes, heteroarenes, and various radicals, including N3, P(O)R2, and CF3.

Transition-Metal-Free, Intermolecular Azidoheteroarylation of Alkenes: Efficient Access to β-Azidoalkylated Quinoxalinones and Preliminary Antifungal Evaluation Against Magnaporthe grisea

“…10 Nagib and co-authors disclosed the three-component difunctionalization of electron-rich alkene (ethyl vinyl ether) with heteroarenes and different radical precursors, including N 3 , P(O)R 2 , and CF 3 . 11 On the other hand, quinoxalinones are prevalent heterocyclic compounds in medical chemistry because of the unique chem-biological properties, 12 which has attracted the intensive development of straightforward approach for the synthesis of functionalized quinoxalinones. 13 We thus envisioned that, if both azido and quinoxalinones group could be simultaneously introduced into organic compounds, efficient synthesis of heteroarylated organoazides and related nitrogen-containing compounds might be expected, which could provide general avenue to install diverse quinoxalinones into the original lead drugs and agrichemicals for the bioactivity modulation ( Figure 1).…”

“…er oxidants including K 2 S 2 O 8 , TPBP, and TBHP generated worse results (entries [10][11][12], prompting us to further optimize the condition. Bubbles were observed from the reaction mixtures when solvent was injected, indicating that the concentration of N 3 radical is perhaps too high.…”

Organoboron Mediated Homolytic Aromatic Substitution of N-Methoxypyridinium Salts

“…In a related manner, three component coupling reactions involving N-methoxypyridinium salts were developed by Baik, Hong and co-workers [31] using a Mn(III)/Ag(I) oxidizing system and by Nagib and co-workers using an iridium based photocatalyst. [32,33] Scheme 1. Radical addition to N-alkoxypyridinium salts.…”

Visible‐Light‐Enabled Trifluoromethylative Pyridylation of Alkenes from Pyridines and Triflic Anhydride

“…[4] Despite impressive advances,t he regioselective functionalization of unblocked pyridines remains ad ifficult challenge. [5] Fore xample,t he Minisci-type C À Ha lkylation of pyridine and quinoline motifs is plagued by poor regioselectivity and overalkylation issues arising in unbiased systems. [6] In this context, it has been well recognized that ac ritical difficulty in the development of the trifluoromethylative pyridylation of alkenes is associated with ac hallenge in achieving regiocontrol over two competing sites (C2 vs.C4) on the pyridine core.…”