914102-11-7Relevant articles and documents
PROCESS FOR THE CARBONYLATION OF ETHYLENICALLY UNSATURATED COMPOUNDS, NOVEL CARBONYLATION LIGANDS AND CATALYST SYSTEMS INCORPORATING SUCH LIGANDS
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Page/Page column 55-56, (2010/04/03)
A novel bidentate catalytic ligand of general formula (I) is described. R represents a hydrocarbyl aromatic structure having at least one aromatic ring to which Q 1 and Q 2 are each linked, via the respective linking group, if present, on available adjacent atoms of the at least one aromatic ring. The groups X 3 and X 4 represent radicals joined via tertiary carbon atoms to the respective atom Q 1 and the groups X 1 and X 2 represent radicals joined via primary, or substituted aromatic ring carbon atom(s) to the respective atom Q 2. A and B represent an optional lower alkylene linking group. Q 1 and Q 2 each represent phosphorus, arsenic or antimony. A process for the carbonylation of ethylenically unsaturated compounds comprising reacting the compound with carbon monoxide in the presence of a source of hydroxyl groups, optionally, a source of anions and catalyst system obtainable by combining a metal of Group 8, 9 or 10 or a compound thereof and the bidentate ligand of general formula (I) is also described.
The methoxycarbonylation of vinyl acetate catalyzed by palladium complexes of [1,2-phenylenebis(methylene)]bis[di(tert-butyl)phosphine]
Rucklidge, Adam J.,Morris, George E.,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
, p. 1783 - 1800 (2007/10/03)
Palladium complexes of [1,2-phenylenebis(methylene)]bis[di(tert-butyl) phosphine] (1) catalyze the methoxycarbonylation of vinyl acetate (=ethenyl acetate) in the presence of methanesulfonic acid (Scheme 1). High selectivities to ester products can be obtained if free phosphine ligand is in excess over the amount of added acid (Table 1). Selectivities to methyl 2-acetoxypropanoate, a precursor to lactate esters, can be as high as 3.6:1 at low temperature and pressure (Table 2). Replacing tBu by iPr groups leads to less-active catalysts and lower selectivities to the branched product. Replacing the phenylene moiety by a naphthalenediyl moiety also gives lower activity, but with similar selectivity to the phenylene-based analogues. Linear hydrocarbon-chain linkers as the backbone instead of the phenylenebis(methylene) linker leads to poor catalysis, except for a propane-1,3-diyl linker, which gives good rates but poor branched selectivity (Table 5). The effect of different reaction conditions on the catalysis is discussed. The syntheses of the new xylene-based diphosphines 2-5 with one to four iPr groups replacing the tBu groups at the P-atoms of 1 and of the ligands 6 and 7 based on 1,2- and 2,3-dimethylnaphthalene are also described (Schemes 2 and 3).
