Selective hydrogenation of alpha,beta-unsaturated oxosteroids with homogeneous rhodium catalysts

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Nunes, RMD (Author) Other; Peixoto, AF (Author) FCUP; Axet, AR (Author) Other; Pereira, MA (Author) Other; Moreno, MJ (Author) Other; Kollar, L (Author) Other; Claver, C (Author) Other; Castillon, S (Author) Other

Journal

Title: Journal of Molecular Catalysis A: Chemical

Vol. 247

Pages: 275-282

ISSN: 1381-1169

Publisher: Elsevier B.V.

Indexing

ISI Web of Knowledge - 8 Citations

Scopus - 9 Citations

Other information

Authenticus ID: P-004-MQN

DOI: 10.1016/j.molcata.2005.11.058

Abstract (EN): A comparative study of the ligand (5-10) effect on the rhodium catalytic activity and selectivity in the homogeneous hydrogenation of alpha, beta-unsaturated oxosteroids (1-4) is reported. The highest activity for C=C reduction was observed with phosphite ligands, being diphosphite 10 the most active. Furthermore, the presence of phosphite 6 significantly enhances the chemo and alpha-diastereoselectivity for the hydrogenation reaction. The beta-methyl groups of the steroidal framework lead to a very high alpha-diastereoselectivity, even in the absence of phosphorous ligands. Substrate 4 is the paradigm presenting higher than 94% a-diastereoselectivity for any catalytic system studied. The catalytic system formed from rhodium and the new diphosphite 10 also revealed a remarkable tendency for the C=O reduction and a noteworthy stability.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8