Page 222 - Catalysts for Fine Chemical Synthesis Vol 1 - Robert & Poignant

210 hydrolysis, oxidation and reduction

1
H-NMR (300 MHz, CDCl 3 ): d 7.25±7.18 (m, 3H), 7.04±7.00 (m, 2H),
5.96 (d, J 7.1 Hz, 1 H), 4.85±4.78 (m, 1 H), 3.65 (s, 3 H), 3.11±2.97 (m, 2H),
1.90 (s, 3 H).
13 C-NMR (75 MHz, CDCl 3 ): d 172.07, 169.52, 135.85, 129.18, 128.51,
127.06, 53.10, 52.21, 37.83, 23.02.

Conclusion
The straightforward synthesis of the diamino FERRIPHOS ligand offers a
convenient access to this class of ferrocenyl ligands [32] and makes this ligand
well suited for applications in asymmetric hydrogenation.
Table 12.5 shows some examples of -acetamidoacrylates that were hydro-
genated with (S)-(R)-diamino FERRIPHOS as ligand [33] .

1 mol%L* NMe 2
CO 2 Me CO 2 Me Ph
1 mol%Rh(COD) 2 BF 4
L*= Ph 2 P Fe
R N(H)Ac H 2 (1bar),MeOH/Toluol,RT R N(H)Ac Ph
Ph 2 P NMe 2
Table 12.5 Asymmetric hydrogenation of a-acetamidoacrylates
using the (S)-(R)-diamino FERRIPHOS ligand.
Substrate Conversion [%] ee [%]
R ˆ H 100 97.8 (S)
R ˆ Ph 100 97.5 (S)
R ˆ 2-Naphthyl 100 97.7 (S)
R ˆ p-Cl-Ph 100 98.7 (S)
R ˆ p-F-Ph 100 97.2 (S)

Furthermore FERRIPHOS ligands bearing alkyl groups instead of dimethy-
lamino substituents proved to be excellent ligands in the asymmetric hydrogen-
ation of a-acetamidoacrylic acids [34] and acetoxy acrylic esters [35] . Their air
stability and the easy modification of their structure make the FERRIPHOS
ligands particularly useful tools for asymmetric catalysis.

REFERENCES

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3. Burk, M.J., Feaster, J.E., Nugent, W.A., Harlow, R.L. J. Am. Chem. Soc., 1993, 115,
10125.
4. Noyori, R. Acta Chemica Scandinavica 1996, 50, 380.
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