Rhodium-Catalyzed Hydroformylation of Allyl Alcohol. A Potential Route to 1,4-Butanediol

Article abstract of DOI:10.1021/jo01299a600

A detailed study of the rhodium-catalyzed hydroformylation of allyl alcohol to 4-hydroxybutanal (1) and 3-hydroxy-2-methylpropanal (2) was carried out, using RhH(CO)(PPh3)3 and its polymer-bound analogues.The reaction is complicated by isomerization of allyl alcohol to propanal, hydrogenation to propanol, and the production of higher boiling products.The product distribution and normal/branched selectivity were studied as a function of the P/Rh ratio, pressure, temperature, H2/CO ratio, and phosphine ligand.Ligands employed included triphenylphosphine, tributylphosphine, triphenyl phosphite, tris(p-chlorophenyl) phosphite, 1,2-bis(diphenylphosphino)ethane, (Ph2PCH2CH2)2PPh (triphos), and 1,1'-bis(diphenylphosphino)ferrocene.The highest n/b selectivities at high conversions were achieved with 1,1'-bis(diphenylphosphino)ferrocene where yields of 1 in excess of 80percent could be routinely achieved at 60 deg C and 800 psi, H2/CO = 1:1.The variation in selectivity with respect to reaction variables was compared to the behavior of olefins in hydroformylations.