Cobalt-catalysed hydroformylation of epoxides in the presence of phosphine oxides

A novel cobalt-catalysed hydroformylation of epoxides to beta-hydroxyaldehydes was developed. Compared to previous works this methodology proceeds under significantly milder conditions (70 degrees C; 40 bar of CO/H2 = 1 : 1). Crucial for the activity of the cobalt catalyst is the use of phosphine oxides, especially tricyclohexylphosphine oxide, as cheap and easily available promoters. The hydroformylation reaction can be easily combined with a consecutive one-pot hydrogenation of the in situ generated beta-hydroxyaldehydes to produce directly 1,3-diols (important intermediates for polyesters and fibres) starting from epoxides. The rapid formation of a mononuclear acyl cobalt carbonyl complex as an intermediate was observed by in situ FTIR spectroscopy. Phosphine oxides showed exceeding performance as promoters for the cobalt-catalyzed hydroformylation of epoxides to beta-hydroxyaldehydes, which were hydrogenated in situ to 1,3-diols, important intermediates for polyesters and fibres.