Commentary on “A New, Efficient and Recyclable Lanthanum(III) Oxide‐Catalyzed CN Cross‐Coupling” by S. Narayana Murthy, B. Madhav, V. Prakash Reddy, and Y. V. D. Nageswar, Adv. Synth. Catal. 2010, 352, 3241–3245

Resolving Heterogeneity Problems and Impurity Artifacts in Operationally Homogeneous Transition Metal Catalysts

“…In another case of what was intended to be a Pd-free Sonogashira coupling (eq ), Pd was identified as an impurity in the CsCO 3 base . In what was originally thought to be a La-catalyzed C–N cross coupling, arguments have been made that trace Cu is the true catalyst . An important clue to the resolution of this case was that the “La-catalyzed” reaction showed the same selectivity characteristics as previously seen for the previously known copper catalyst; in particular, the N , N ′-dimethylethylenediamine (DMEDA) ligand proved best for both. …”

A Highly Versatile Catalytic System forN‐Arylation of Amines with Aryl Chlorides in Water

“…As for ortho-substituted aryl chlorides, the reaction was slower and less efficient and afforded the corresponding 2-methoxy-Nphenylaniline (Scheme 2, 3d) in only 37 % isolated yield after 24 h. This observation was relevant to Cu-catalyzed systems because of steric hindrance. [9] Notably, a much larger excess of benzylamine (6 equiv.) and hexane-2,5-dione (1.5 equiv.)…”

Functionalized imidazolium salt: an efficient catalyst for Buchwald–Hartwig type C–N cross-coupling of (hetero)aryl chlorides/bromides with amines under solvent-, inert gas-, and base-free ambience

“…8 Chan, Evans and Lam also contributed significantly to C–N coupling using Cu(OAc) 2 as a catalyst with an amine base. 9–11 A variety of transition metals, like Pd, 2 Fe, 12,13 Ag, 14 Ni, 15 Au, 16 Rh, 17 and La 18 have been employed as salts or complexes in the production of C–N bonds. In accordance with the literature, C–N coupling necessitates a strong base.…”