Modular Bis(oxazoline) Ligands for Palladium Catalyzed Allylic Alkylation: Unprecedented Conformational Behaviour of a Bis(oxazoline) Palladium 3-1,3-Diphenylallyl Complex

Abstract

Mit einem IC50‐Wert von 9 nM ist 1 der wirksamste bekannte Disubstrat‐Inhibitor für Catechol‐O‐Methyl‐Transferase (COMT). Die Inhibierung von COMT ist für die Therapie der Parkinson‐Krankheit interessant, da hierdurch gewährleistet ist, dass ein größerer Prozentsatz von – in Form von Dopamin – oral verabreichtem L‐Dopa den Rezeptor im Gehirn erreicht. Die Struktur eines Komplexes aus COMT und 1 wurde mit einer Auflösung von 2.6 Å aufgeklärt.

A General Route to Construct Diverse Multifunctional Fe3O4/Metal Hybrid Nanostructures

“…The NOESY also indicated an exchange between the allylic terminal protons located trans to the pyridine moiety of isomers A and C (Figure 9). This confirms the η 3 ‐η 1 ‐η 3 movement for the exchange between isomers A and C 35. In addition, the fact that no other H anti ‐H syn exchange was observed indicates that the exchange took place by means of the selective opening of one of the terminal PdC bonds.…”

“…To determine the ee value by HPLC (Chiralcel OD, 0.5 % 2‐propanol/hexane, flow 0.5 mL min −1 ), a sample was filtered over basic alumina using dichloromethane as the eluent 42. For compounds 21 , 27 , and 34 , the conversion and enantiomeric excess were determined by GC 35. For compound 33 , the conversion was measured by 1 H NMR spectroscopy.…”

A New Class of Modular P,N‐Ligand Library for Asymmetric Pd‐Catalyzed Allylic Substitution Reactions: A Study of the Key Pd–π‐Allyl Intermediates

“…The NOESY also indicated an exchange between the allylic terminal protons located trans to the oxazole moiety of isomers B and D (Figure 2). This confirms the η 3 –η 1 –η 3 movement for the exchange between isomers B and D 24. In addition, the fact that no other H anti –H syn exchange was observed indicates that the exchange took place by means of the selective opening of one of the terminal PdC bonds.…”

(+)-2,2-Bis[2-(4R,5S-diphenyl-1,3-oxazolinyl)]propane and (−)-2,2-Bis[2-(4S,5R-diphenyl-1,3-oxazolinyl)]propane

“…14 Also, the Cu(I)-catalyzed allylic oxidation of cycloalkenes in the presence of ligand (+)-1 showed an appreciable asymmetric induction, as the allylic benzoates 30 were obtained with up to 80% ee (eq 10). 14 25 24 + (+)-1/Cu(OTf) 2 …”

“…The Mukaiyama-Michael reaction of α -phenylsulfonyl enones 31 with 2-(trimethyl-silyloxy)furan 32 (eq 10) was usefully catalyzed by the complex of (+)-1 with Cu(OTf) 2 (11) Reaction showed very good yields, excellent anti selectivities, and almost complete enantioselectivity with all the substituents tested (ee from 95 to 99%, Table 3). Substrate 31 was enantioselectively alkylated by conjugate radical addition with alkyl iodides 34.…”