Palladium‐Catalyzed ortho‐Heteroarylation of β‐Arylethylamines Through Cross‐Dehydrogenative Coupling

Abstract

A palladium‐catalyzed oxidative C–H/C–H cross‐coupling of oxalyl amide‐protected β‐arylethylamines and heteroarenes has been developed. The methodology presented a broad substrate scope, great functional group tolerance, and good to excellent yields for the synthesis of ortho‐thiophenylated β‐arylethylamines. The installed thiophene functional group can promote a second C–H functionalization, such as alkynylation and arylation.

Palladium-catalyzed cross-dehydrogenative coupling of (hetero)arenes

“…Similar to pyrroles and furans, thiophenes have also found use as substrates in Pd-catalyzed CDC reactions with arenes. In 2020, Shi, Zhao and co-workers described the coupling of several 2-substituted thiophenes with oxalyl amide-protected β-arylethylamines (Scheme 24): 52 working under ligand-free conditions with Pd(OAc) 2 (10 mol%) as the catalytic precursor, Ag 2 CO 3 (1.5 equiv.) as the oxidizing agent, NaOAc (1.0 equiv.)…”