Aqueous conditions hydroxycarbonylation

In order to keep the mild conditions, hydroxycarbonylation has been performed in biphasic media, maintaining the catalyst in the aqueous phase thanks to water-soluble mono- or diphosphine ligands. In the presence of the sodium salt of trisulfonated triphenylphosphine (TPPTS), palladium was shown to carbonylate efficiently acrylic ester [19], propene and light alkenes [20,21] in acidic media. For heavy alkenes the reduced activity due to the mass transfer problems between the aqueous and organic phases can be overcome by introducing an inverse phase transfer agent, and particularly dimeihyl-/-i-cyclodextrin [22,23]. Moreover, a dicationic palladium center coordinated by the bidentate diphosphine ligand 2,7-bis(sulfonato)xantphos (Fig. 2) catalyzes, in the presence of tolylsulfonic acid for stability reasons, the hydroxycarbonylation of ethylene, propene and styrene and provides a ca. 0.34 0.66 molar ratio for the two linear and branched acids [24],... 

Addition of diethyl malonate to diethyl vinylphosphonate,tetraethyl ethenylidenediphos-phonate/ and diethyl l-ethenylidene-Z-oxoalkylphosphonates nnder basic conditions has been described. The em-diphosphonate resulting from the addition of diethyl malonate to tetraethyl ethenylidenediphosphonate in the presence of EtONa/EtOH after saponification with KOH in aqueous THF and acidihcation is decarboxylated to give the tetraethyl 3-(hydroxycarbonyl)-l,l-propylidenediphosphonate in 65% yield (Scheme 8.61... 

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