The water-soluble complexes [Rh(CO)(Pz)(L)](2) and [HRu(CO)(CH3CN)(L)(3)][BF4] [L=TPPMS (m-sulfonatophenyl-diphenylphosphine) and TPPTS (tris-m-sulfonato-phenylphosphine)] were used for the first time as catalyst precursors for the hydroformylation of eugenol, estragole, safrole and trans-anethole under moderate conditions in biphasic media. Under mild reaction conditions the substrates showed the following reactivity order: eugenol > estragole approximate to safrole >> trans-anethole. The use of cetyltrimethylammonium chloride (CTAC) as phase transfer agent inhibits the isomerization reaction, reaching high selectivity for the hydroformylation products (80-94%). The catalytic phase can be recycled up to four times with a decrease in the activity over time but maintaining its high selectivity. (C) 2011 Elsevier B.V. All rights reserved.