NaNH₂ as a Nitrogen Source and Base to Synthesize Triarylamines from Aryl Halides Using Pd-Catalyzed C–N Coupling

Abstract

Triarylamines (TAAs) are excellent core structures for multifunctional materials. Reversible single-electron oxidation is the key to versatile applications. Synthesizing these from feedstock materials is inevitable. Here, we report the one-pot synthesis of TAAs from aryl halides and inexpensive NaNH 2 as a nitrogen source and base (dual role). The Pd/ Xantphos catalytic system shows excellent selectivity toward TAAs from aryl bromides without adding organic amines and an additional base. Various para substituents on the aryl ring show good functional group tolerance in the presence of NaNH 2 , resulting in moderate to excellent yield (20−91%). Even though the meta-substituted aryl bromides give TAA products in moderate to excellent yields (20−81%), the ortho substitution leads to only diarylamine products. TAAs from aryl chlorides can be achieved only by changing the ligand to Xphos. The mechanistic investigation suggests that three sequential C−N cross-coupling reactions give the TAA products in the presence of NaNH 2 . The photophysical and electrochemical properties of TAAs and corresponding radicals were tunable based on substitution patterns.