Asymmetric homogeneous hydrogenation of 2,5-disubstituted furans.
A homogeneous catalyst system for the asymmetric cis-hydrogenation of 2,5-disubstituted furans leading to 2',3'-dideoxynucleoside analogues is described. Best enantioselectivities (ee values of up to 72%) were obtained with cationic rhodium complexes ligated by diphospholanes of the butiphane family. The selectivity of the hydrogenation was reversed by the addition of a base or a polar protic solvent in certain cases. Ferrocene- and proline-based systems gave significant, but lower, ee values.
Feiertag
Petra
P
Institut für Organische Chemie, Technische Universität Graz, A-8010 Graz, Austria.
Albert
Martin
M
Nettekoven
Ulrike
U
Spindler
Felix
F