Steroids asymmetric hydroformylation

I. Vinylarenes Styrene and its derivatives have been most intensively studied as substrates for asymmetric hydroformylation because of their high reactivity and high selectivity for yielding branched aldehydes. Furthermore, aldehydes derived from these olefins can be converted to various pharmaceuticals such as non-steroidal antiinflammatory agents (vide infra) [74]. Representative results for the reaction of styrene (I6a) are summarized in Scheme 7.3 and Table 7.1. 

We describe the extension of this class of bisphosphite catalysts to asymmetric hydroformylation and hydrocyanation of vinylarenes.(3) These enantiose-lective catalytic transformations are employed for the asymmetric synthesis of S-Naproxen, a widely used non-steroidal anti-inflammatory drug (NSAID). Factors which influence regioselectivity and enantioselectivity, as well as characterization of the catalyst resting states, are discussed. 

Gladiali DS, Faedda G, Marchetti M, Botteghi C. Asymmetric hydrogenation, hydroformylation and hydro-carbalkoxylation of olefins by transition metal complexes with steroidal phosphines. J. Org. Chem. 1983 244(3) 289-302. 

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