The 3d‐metal catalyst Mn(CO)5Br was found to efficiently promote ortho C−H allylations of arenecarboxylates in the presence of neocuproine as the ligand. Despite the simplicity of directing group and catalyst system, the selectivity goes well beyond the state‐of‐the‐art in that mono‐allylated products are obtained exclusively with high selectivities for the least hindered ortho‐position. The directing group can optionally be removed by in situ decarboxylation, opening up a regioselective entry to allyl arenes. The preparative utility of the process and its othogonality to other approaches was demonstrated by 44 products with otherwise hard‐to‐access substitution patterns, including 3‐bromo‐allylbenzene, 3‐allylbenzofuran, or 5‐allyl‐2‐methylnitrobenzene.
Starting from commercially available DMSAuCl and diazonium salts, cationic [N∧C∧N
]AuIII complexes were synthesized in a selective, photosensitizer‐free, photochemical reaction by irradiation with blue LED light. This new protocol represents the first easy synthesis of these types of pincer complexes in moderate to excellent yield starting from a readily available gold(I) precursor with nitrogen as the only by‐product. Owing to the disadvantages of known protocols, especially the toxicity in the case of a transmetalation with mercury or the necessity for a mostly twofold excess of a gold precursor, this method offers an attractive alternative towards this kind of gold(III) complexes. In addition, the first arylated [N∧C∧N
]Au(III) pincer complex was synthesized by using this technology.
In Gegenwart von Neocuproin als Ligand vermittelt der 3d‐Metallkatalysator Mn(CO)5Br erffizient ortho‐C–H‐Allylierungen aromatischer Carboxylate. Trotz der Einfachheit der dirigierenden Gruppe und des Katalysatorsystems geht die Selektivität weit über den Stand der Technik hinaus, da ausschließlich mono‐allylierte Produkte mit hoher Selektivität für die am wenigsten gehinderte ortho‐Position erhalten werden. Die dirigierende Gruppe kann optional durch in situ Decarboxylierung entfernt werden, was einen regioselektiven Zugang zu Allylarenen eröffnet. Der präparative Nutzen des Verfahrens und seine Orthogonalität zu anderen Ansätzen wurde anhand von 44 Produkten mit ansonsten schwer zugänglichen Substitutionsmustern nachgewiesen, darunter 3‐Brom‐allylbenzol, 3‐Allylbenzofuran oder 5‐Allyl‐2‐methylnitrobenzol.
Allylation. In their Communication (e202301839), Lukas J. Gooßen et al. report a simple manganese catalyst for the ortho‐C−H allylation of benzoic acids. The reaction can be combined with an in situ decarboxylation, giving access to allylarenes in substitution patterns that are otherwise hard to obtain.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.