title: Heteroatom-substituted secondary phosphine oxides (HASPOs) as decomposition products and preligands in rhodium-catalysed hydroformylation.
abstract: O,O'-3,3'-Di-tert-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diyl phosphonate (1) is the hydrolysis product of several mono- and bis-phosphites used as ligands in industrial hydroformylation and other catalytic reactions. As a result of a tautomeric equilibrium, this pentavalent heteroatom-substituted phosphine oxide (HASPO) can rearrange to the corresponding trivalent phosphorus compound. The latter is able to react with typical rhodium-containing precursors frequently used for the generation of catalysts. The resulting species were characterised by NMR spectroscopy and X-ray structure analysis. Proof is given that a rhodium complex of 1 forms an active hydroformylation catalyst. Moreover, 1 can add to aldehydes, which are generated as products in the hydroformylation. Thus a broad range of subsequent reactions can be associated with the degradation of the original phosphite ligands, which has a strong influence on the overall outcome of the hydroformylation reaction.
authors.affiliation: Leibniz-Institut für Katalyse an der Universität Rostock eVA-Einstein-Str 29a, 18059 Rostock, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Christiansen
authors.forename: Detlef
authors.initials: D
authors.lastname: Selent
authors.forename: Anke
authors.initials: A
authors.lastname: Spannenberg
authors.forename: Martin
authors.initials: M
authors.lastname: Köckerling
authors.forename: Helmut
authors.initials: H
authors.lastname: Reinke
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baumann
authors.forename: Haijun
authors.initials: H
authors.lastname: Jiao
authors.forename: Robert
authors.initials: R
authors.lastname: Franke
authors.forename: Armin
authors.initials: A
authors.lastname: Börner