Palladium(II) Complexes of 2-Dimethylamino-2‘- diphenylphosphino-1,1‘-binaphthyl (MAP) with Unique P,C_σ-Coordination and Their Catalytic Activity in Allylic Substitution, Hartwig−Buchwald Amination, and Suzuki Coupling

Small Substituents Make Large Differences: Aminopyrimidinyl Phosphanes Undergoing C–H Activation

“…[10] They were also able to prove by X-ray crystal structural analysis that the MAP ligand coordinates to Pd through an unusual P,C σ -chelation rather than by a P,N-binding mode. [11] Buchwald et al reported that the palladium complexes of ligands L2b,c show excellent reactivities in asymmetric Suzuki couplings. [12] Faller et al prepared and characterised two allyl palladium complexes of L1 type ligands.…”

Reactivity control in palladium-catalyzed reactions: a personal account

“…However, rather surprisingly, this mixture was dominated by 68 (Â/85%), a five-membered palladacycle with an unusual P ,C s -coordination. Crystallization of the 64/PdCl 2 mixture afforded 68 as a single product, whose structure was confirmed by X-ray crystallography [54]. Its formation can be understood in terms of the enamine-like behavior of the aminonaphthalene moiety in 64, which can encourage an electrophilic attack at the ipso -carbon [54]; furthermore, formation of a five-membered palladacycle, as in 68, should be thermodynamically favored over the sevenmembered chelate 69, which apparently contributes to the overall outcome.…”

“…In order to elucidate the mode of coordination of 64 to PdCl 2 (Scheme 17) [54,56], we teamed up with Guy Lloyd-Jones at Bristol [57]. The 1 H-, 13 C-and 31 P-NMR spectroscopy indeed confirmed the presence of the Scheme 15. Scheme 16. expected P ,N -chelate 69 in the solution but only as a minor component (Â/10%).…”

“…Its formation can be understood in terms of the enamine-like behavior of the aminonaphthalene moiety in 64, which can encourage an electrophilic attack at the ipso -carbon [54]; furthermore, formation of a five-membered palladacycle, as in 68, should be thermodynamically favored over the sevenmembered chelate 69, which apparently contributes to the overall outcome. Similar h 1 -coordination pattern has been found by us in the p-allylpalladium complex of MAP (71), whereas the MOP complex 72 exhibited h 2 -coordination to the C(1) Á/C(2) bond (Scheme 18) [54,56]. Recently, Buchwald has reported a crystallographic characterization of Pd(0) complex 73, which also exhibits h 2 -coordination [58].…”

Organotrifluorborate und einfach koordinierte Palladiumkomplexe als Katalysatoren – die perfekte Kombination für die Suzuki‐Miyaura‐Kupplung

“…[19] Brown und Mitarbeiter ließen eine detaillierte Studie folgen, in der sie zeigten, dass der Mechanismus der oxidativen Addition an [Pd(PR 3 ) 2 ]-Komplexe von der Größe der Alkylgruppen am Phosphan abhängt. [20] 23] Weitere erfolgreiche Ligandenfamilien mit ähnlichen Strukturelementen wurden beschrieben; am bekanntesten sind wohl die in Schema 6 gezeigten CataCXium-Liganden. [24] Aus ähnlichen Gründen wie die Phosphane haben sich auch N-heterocyclische Carbene (NHCs) ausgesprochen gut bewährt (Schema 7).…”