Palladium-Allyl Phosphoramidite Complexes:  Solid-State Structures and Solution Dynamics

Abstract

Several mono-phosphoramidite and bis-phosphoramidite 2-methallyl and 1,3-diphenylallyl allyl complexes of Pd(II) have been prepared. The solid-state structure for one of these has been determined. The mono-phosphoramidite chloro-allyl complexes of Pd(II) exist in two isomeric forms in solution. 1 H, 1 H NMR exchange spectroscopy reveals that the dinuclear species [Pd(µ-Cl)(η 3 -CH 2 C(Me)CH 2 )] 2 is involved in the interconversion between the two isomers. There is evidence to suggest that phosphoramidite dissociation is not responsible for this exchange. The cationic η 3 -2-methallyl bis-phosphoramidite Pd complexes reveal nonequiValent 31 P resonances, as a consequence of slow allyl dynamics and in agreement with the preliminary X-ray structure.

Diphosphorus Ligands Containing a P‐Stereogenic Phosphane and a Chiral Phosphite or Phosphorodiamidite – Evaluation in Pd‐Catalysed Asymmetric Allylic Substitution Reactions

“…Hence, two singlets at δ = 1.3–2.0 ppm account for the methyl group, whereas two sets of four peak in the range δ = 2.3–4.8 ppm can be assigned to the four protons of the methallyl group. As expected,[14a], [14d], , the anti protons usually appear at higher fields ( δ = 2.3–3.8 ppm) as doublets with coupling constants of ca. 10 Hz owing to the coupling with the phosphorus atom at the relative trans position.…”

Asymmetric trapping of zwitterionic intermediates by sulphur ylides in a palladium-catalysed decarboxylation-cycloaddition sequence

“…Significantly, many reactive Pd-allyl phosphoramidite complexes have been isolated, and their configurations have been established through X-ray diffraction (see Supplementary Fig. 40) and twodimensional (2D) NMR technologies 47,48 . On the basis of these advances, we proposed a favourable configuration (Fig.…”

1H‐DOSY‐Spektren von Liganden für hochenantioselektive Reaktionen – eine schnelle und einfache Methode zur Optimierung katalytischer Reaktionsbedingungen

“…B. an ciskoordinierten Liganden in einem Bis(phosphonit)-PlatinKomplex und in einem Bis(phosphoramidit)-PalladiumKomplex, deren cis-Anordnung auf schwache intermolekulare Wechselwirkungen zurückgeführt wurde. [13,14] Wir berichteten kürzlich von einer temperaturabhängigen gegenseitigen Umwandlung unterschiedlicher Phosphoramidit-Kupfer-Komplexe, die wahrscheinlich durch LigandLigand-Wechselwirkungen vermittelt wird. [15] …”