The regioselectivehydroformylation of enamides with a catalyst derived from monodentate phosphites and Rh(acac)(CO)2 was studied. In the hydroformylation of N-vinylphthalimide, all the biphenol-based ligands led to the branched aldehyde; the fastest reaction was observed when using a sterically bulky phosphite. The olefins (E)-N-propenylphthalimide, vinylpyrrolidone, vinylcaprolactam and vinylcarbazole