Broad-Scope Amination of Aryl Sulfamates Catalyzed by a Palladium Phosphine Complex

Abstract

Among phenol-derived electrophiles, aryl sulfamates are attractive substrates since they can be employed as directing groups for C−H functionalization prior to catalysis. However, their use in C−N coupling is limited only to Ni catalysis. Here, we describe a Pd-based catalyst with a broad scope for the amination of aryl sulfamates. We show that the N-methyl-2-aminobiphenyl palladacycle supported by the PCyp 2 Ar Xyl2 ligand (Cyp = cyclopentyl; Ar Xyl2 = 2,6-bis(2,6dimethylphenyl)phenyl) efficiently catalyzes the C−N coupling of aryl sulfamates with a variety of nitrogen nucleophiles, including anilines, primary and secondary alkyl amines, heteroaryl amines, N-heterocycles, and primary amides. DFT calculations support that the oxidative addition of the aryl sulfamate is the rate-determining step. The C−N coupling takes place through a cationic pathway in the polar protic medium.

Nanoparticles as Heterogeneous Catalysts for ppm Pd-Catalyzed Aminations in Water

“…Illustrated in Scheme are several comparison cases focused on existing literature approaches to C–N bond formation. ,, Aminations arriving at products 39 – 42 indicate that the catalytic system described here based on [Pd­(crotyl)­Cl] 2 – t BuXPhos, in general, appears to be the most effective known. It allows for aminations at lower catalyst loadings of metal, takes place in predominantly aqueous micellar media, and leads to typically faster couplings than the corresponding reactions in organic solvents.…”