Naslov
Asymmetric hydrogenation of alpha-Arylpropenoic acids catalyzed by Rhodium(I) complexes of chiral ligands derived from some monosaccharides

Autori
Šunjić, Vitomir ; Habuš, Ivan ; Comisso, Giovanni ; Moimas, Flavio

Izvornik
Gazzetta Chimica Italiana (ISSN 0016-5603) European Journal of Organic Chemistry (od 1998) (1434-193X) 119 (1989); 229-233

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Prochiral precursosrs; (+)-Ketoprofen; and (+)-Naproxen; bidentate ligand

Sažetak
Prochiral precursosrs, 3 and 6, of (+)-Ketoprofen, 1, and (+)-Naproxen, 2, are hydrogenated in the presence of various Rh(I) complexes of chiral diphenylphosphines and diphenylphophinites (15-21). The last four ligands (18-21) are derived from the most widespread monosaccharides, D-glucose, D-xylose, D-galactose and L-arabinose. The optical yields (e.e'.s. in %) varies from low to medium (~10-50%), indicating that none of the substrates 3 and 6 behave as bidentate ligand within any of the examined catalytic species. The highest e.e. (45%) was obtained with 6, using the Rh(I) complex of 20 as catalyst. No "double asymmetric induction" either intramolecular (in 8) or intermolecular (in 13) has been reached when hydrogenation with 21 was tried ; diastereomeric excess (d.e.) (~25%) only approaches the e.e'.s. obtained for prochiral substrates 3 and 6 with the complexes of 19 and 20.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA