The water-soluble Pd(tppts)(3) complex (tppts=P(C6H4-m-SO3Na)(3)) is an active catalyst for the carbonylation of benzylic type alcohols in aqueous/organic two-phase systems in the presence of a Bronsted acid cocatalyst. For example, 1-(4-isobutylphenyl)ethanol afforded 2-(4-isobutylphenyl)propionic acid in 82% selectivity at 83% conversion and 5-hydroxymethylfurfural (HMF) gave 5-formylfuran-2-acetic acid in 72% selectivity at 90% conversion. In the latter case, use of an acid with a strongly coordinating anion led to the preferential formation of the reduction product 5-methylfurfural (MF), e.g. HI afforded MF in >99% selectivity. Pd(tppts)3 is also an usual active catalyst (T.O.F.>2500) for the biphasic hydrocarboxylation of propene to n- and isobutyric acid, being substantially more active than the analogous Pd/PPh3 in organic media.