Hydroformylation of methyl acrylate

Mortreux and co-workers compared the activity of the SAPC catalysts with that of the homogeneous analogue in the hydroformylation of methyl acrylate [69]. They observed an activity for the SAPC that was strongly dependent on the amount of water present in the system. More remarkably, the optimised activity of the SAPC was higher than that of the homogeneous systems. This effect was ascribed to the polar interactions between the substrate and the silica support. This effect was not observed for nonpolar substrates such as propene, which supported the hypothesis. 

Hydroformylation of methyl acrylate provides racemic methyl 2-formylpropanoate (Scheme 4.17, a-aldehyde) which can be enzymatically reduced to yield important chiral 3-hydroxypropanoic acid derivatives [154]. This reaction was catalyzed by the Rh/PNS (27) and Rh/PC (25) catalysts in... 

Figure 6 Rhodium-catalysed hydroformylation of methyl acrylate using various ligands.130-423...

Attempts have been made to apply the oxoreaction for the synthesis of fine chemicals. Hydroformylation of methyl acrylate to give an a-branched aldehyde is useful in providing chiral building blocks after enzymatic hydrogenation [Eq. (6)]. 

As reported above, a literature survey shows that the hydroformylation of this class of alkene has been scarcely investigated. Indeed, these studies have been devoted exclusively to the hydroformylation of arylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethoxyethyl acrylate, and 2-ethylhexyl acrylate (Eq. 4) [18-21], Most attention has been focused on the hydroformylation of methyl acrylate to 2-formylpropanoate ester since the latter is used extensively for the synthesis of pharmaceuticals and may also be considered as a potential source of methyl methacrylate [18]. 

Hydroformylation of acrylate esters is a potentially very important reaction since the branched aldehyde product gives an entry point to production of important pharmaceuticals and methacrylate ester monomers. Hydroformylation of methyl acrylate (Scheme 20) proceeded in toluene with [Rh(acac)(CO)2] + PlCeHsla at 50°C and 5 MPa CO/H2 with a TOF of 225 h , aldehyde yield 95.4% and a branched to normal aldehyde ratio of more than 200 (165). In an aqueous organic biphasic system (40 mL toluene -I-10 mL water), the initial TOF increased to 545 h, retaining the high regioselectivity (b/n = 128). This effect is not unprecedented— polar solvents may facilitate reactions with polar intermediates or products which are strongly solvated. However, when the reaction was catalyzed with the same Rh-catalyst in a supported aqueous phase on silica gel. 

The resulting alcohol was esterified with ClPPh2 to produce the corresponding phosphinite. In rhodium-catalyzed hydroformylation of methyl acrylate, the P,Af-ligand induced the formation of the branched aldehyde with... 

Faraone and coworkers studied the hydroformylation of methyl acrylate by using a cationic rhodium complex bearing a / Af-ligand derived from (—)-menthone (Scheme 4.82) [57]. The branched aldehyde was preferentially formed with 92% ee. 

Mortretox and colleagues [36] discovered that also the rate of the hydroformylation of methyl acrylate can be greatly enhanced by the reaction in the biphasic system water/toluene in comparison to the reaction in neat toluene (Scheme 7.6). 

Scheme 7.6 Comparison of the rhodium-catalyzed hydroformylation of methyl acrylate in...

Fig. 8 [215]. Influence of water content on reaction velocity of hydroformylation of methyl acrylate in the presence of methanol as solvent...

Though SAP systems usually exhibit a better activity than biphasic systems, both are in most cases inferior to simple homogeneous reactions. The hydroformylation of methyl acrylate is an example of the entirely different behavior. Hydroformylation of acrylic acid derivatives can be of considerable industrial importance [140], as it gives mainly formylpropionic acids, which are viable precursors of methacrylate monomers and can be used for preparation of several important pharmaceuticals ... 

Fremy, G. Monflier, E. Carpenter, J.F. Castanet, Y. Mortreux, A. (1995) Enhancement of catalytic activity for hydroformylation of methyl acrylate by using biphasic and supported aqueous-phase systems, Angew. Chem. Int. Ed. Engl, 34,1474-6. 

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