1241982-03-5Relevant academic research and scientific papers
Cycloaddition of Vinylphosphine Oxides to α-Oxy- o-xylylene as a route to Phosphorylated Naphthyl and Biaryl Scaffolds
Frynas, S?awomir,?astawiecka, El?bieta,Kozio?, Anna E.,Flis, Anna,Pietrusiewicz, K. Micha?
, p. 1818 - 1832 (2019)
α-Oxy-o-xylylene, a highly reactive diene readily accessible from benzocyclobutenol, undergoes Diels-Alder reaction with vinylphosphine oxides, yielding the corresponding 2-phosphorylated 1-hydroxy-1,2,3,4-tetrahydronaphthalenes in excellent yields. Use of unsubstituted and trans-2-aryl-substituted vinylphosphine oxides leads to cycloadducts with complete regioselectivity and with cis/trans selectivity up to 19:1 in the most favorable case. In the case of P-stereogenic trans-2-aryl-substituted vinylphosphine oxides, a virtually complete chirality transfer from P to C can be achieved. Dehydration and aromatization of the obtained cycloadducts bearing the resolved P-stereogenic phosphinoyl groups can be carried out to afford the valuable P-stereogenic and axially chiral phosphorylated 1,2′-binaphthyl ring system. Cases of restricted rotation around Csp3-Csp2 single bond in some tetrahydronaphthalene cycloadducts have also been revealed.
Ferrocenyl-aryl based trans-chelating diphosphine ligands: Synthesis, molecular structure and application in enantioselective hydrogenation
Schuecker, Raffael,Mereiter, Kurt,Spindler, Felix,Weissensteiner, Walter
experimental part, p. 1063 - 1074 (2010/06/17)
Potentially trans-chelating diphosphine ligands based on a ferrocenyl-aryl backbone were synthesised in a four-step sequence and the molecular structures in the solid state of two representatives were determined by X-ray diffraction. High throughput screening of these ligands in rhodium-, ruthenium- and iridium-mediated hydrogenations of a variety of alkenes and ketones revealed that these ligands can deliver high enantioselectivity for alkenes (up to 98% ee) but are less selective when ketones are used as the substrates. The coordination behaviour of one ligand in its square planar palladium and platinum dichloride complexes was studied by 31P NMR and only trans-chelated complexes, together with oligomeric by-products, were observed. Reaction with the (p-cymene)ruthenium dichloride dimer, [RuCl2(pcymene)] 2, resulted in a mixture of diastereomeric complexes.
