Cation Radical Accelerated Nucleophilic Aromatic Substitution via Organic Photoredox Catalysis

Nucleophilic aromatic substitution
(SNAr) is a direct
method for arene functionalization; however, it can be hampered by
low reactivity of arene substrates and their availability. Herein
we describe a cation radical-accelerated nucleophilic aromatic substitution
using methoxy- and benzyloxy-groups as nucleofuges. In particular,
lignin-derived aromatics containing guaiacol and veratrole motifs
were competent substrates for functionalization. We also demonstrate
an example of site-selective substitutive oxygenation with trifluoroethanol
to afford the desired trifluoromethylaryl ether.