Rh-catalyzed hydroformylation of allyl acetate toward 4-acetoxybutyraldehyde: The crucial step in production of 1,4-butanediol via hydroformylation/hydrogenation sequence

The synthesis protocol for 1,4-butanediol via two-step hydroformylation-hydrogenation sequence using allyl acetate as the starting material has attracted much attention in industry. In this work, the first-step hydroformylation of allyl acetate determining the overall efficiency of this protocol was studied. Based on the phosphine screening and reaction condition optimization allyl acetate, Xantphos-modified Rh(acac)(CO)₂ catalytic system proved highly efficient for hydroformylation of allyl acetate, giving the target product of 4-acetoxybutanal in the yield of 80%. This catalytic system is advantageous with excellent regioselectivity to the linear product of 4-acetoxybutanal as well as the recyclability up to 10 runs without activity loss, demonstrating its remarkable stability required for large-scale application. The control experiments were conducted to shed light on the involved reaction pathways for generation of target 4-acetoxybutanal and the related side-products.