Scheme 4 summarizes some of successful phosphine-phosphite ligands for the asymmetric hydroformylation of vinyl arene. The enantioselectivity depends on the configuration of both the binaphthyl moieties. The best enantioselectivity is observed when the configurations of the two binaphthyl moieties are opposite.

Scheme 4. Rh-Catalyzed Asymmetric Hydroformylation of Styrene. Enantioselectivities obtained at 100 bar of syn gas and 60°C are shown in brackets.

9.1.2 Reaction of Vinyl Acetate

The reaction of vinyl acetate is more challenging compared to that of vinylarenes. This process affords 2- and 3- acetoxy propanals with high selectivity (Scheme 5). Ethyl acetate and acetic acid are produced as by-products.

Scheme 5

Scheme 6 illustrates some of the successful ligands for the Rh-catalyzed hydroformylation of vinyl acetate. The enantioselectivity of the reactions are shown in the brackets.

Scheme 6