Ylide‐functionalized phosphine ligands (YPhos) were rationally designed to fit the requirements of Buchwald–Hartwig aminations at room temperature. This ligand class combines a strong electron‐donating ability comparable to NHC ligands with high steric demand similar to biaryl phosphines. The active Pd species are stabilized by agostic C−H⋅⋅⋅Pd rather than by Pd–arene interactions. The practical advantage of YPhos ligands arises from their easy and scalable synthesis from widely available, inexpensive starting materials. Benchmark studies showed that YPhos‐Pd complexes are superior to the best‐known phosphine ligands in room‐temperature aminations of aryl chlorides. The utility of the catalysts was demonstrated by the synthesis of various arylamines in high yields within short reaction times.

Ylide-functionalized phosphine (YPhos) ligands allow the palladium-catalyzed α-arylation of alkyl ketones with aryl chlorides with record setting activity. Using a cyclohexylsubstituted YPhos ligand, a wide range of challenging ketone substrates was efficiently and selectively monoarylated under mild conditions. A newly designed YPhos ligand bearing tert-butyl groups on the coordinating phosphorus atom is already active at room temperature. The synthetic potential was demonstrated by gram-scale reactions and the succinct synthesis of εcaprolactone derivatives.

A carboxylate-directed ortho-C-H functionalization has been developed and it allows the regiospecific introduction of allyl residues to benzoic acids. In the presence of a [Ru(p-cymene)Cl ] and K PO , benzoic acids react with allyl acetates at only 50 °C to give the corresponding ortho-allylbenzoic acids. The protocol is generally applicable to both electron-rich and electron-poor benzoic acids in combination with linear and branched allyl acetates. The products can be further functionalized in situ, for example, by double-bond migration, lactonization, or decarboxylation.

Ylid‐funktionalisierte Phosphanliganden (YPhos) wurden entwickelt, um den Voraussetzungen einer Buchwald‐Hartwig‐Aminierung bei Raumtemperatur zu genügen. Diese Ligandenklasse kombiniert ein besonders hohes Elektronendonorvermögen, vergleichbar mit dem von NHC‐Liganden, mit hohem sterischem Anspruch ähnlich jenem von Biarylphosphanen. Die aktiven Pd‐Spezies sind dabei über agostische C‐H⋅⋅⋅Pd‐ und nicht über Pd‐Aren‐Wechselwirkungen stabilisiert. Der praktische Vorteil dieser YPhos‐Liganden liegt insbesondere in deren einfacher und skalierbarer Synthese ausgehend von leicht zugänglichen sowie günstigen Startmaterialien. Benchmark‐Untersuchungen zeigten, dass YPhos‐Pd‐Komplexe den üblicherweise verwendeten Phosphanliganden in Aminierungen von Arylchloriden bei Raumtemperatur überlegen sind. Der enorme Nutzen dieses Katalysatorsystems konnte durch die Synthese zahlreicher Arylamine in sehr guten Ausbeuten bei geringer Reaktionszeit aufgezeigt werden.