The product distribution in the hydroformylation of α, β-unsaturated esters (ethyl acrylate, methyl methacrylate, methyl crotonate, and methyl tiglate) catalyzed by Rh 2 Cl 2 (CO) 4 was studied at 150° C under 100 atm of synthesis gas (CO/H 2= 1/1) in the absence or presence of various additional phosphorus ligands. In order to attain a high selectivity of α-formylation (> 80%), the addition of shorter methylene-chained diphosphines (R 2 P (CH 2) n PR 2, R ...
