Preparation of C2-Symmetric Bis[2-(diphenylphosphino)ferrocen-1-yl]- methane and Its Use in Rhodium- and Ruthenium-Catalyzed Hydrogenation

✍ Scribed by Yaping Wang; Walter Weissensteiner; Kurt Mereiter; Felix Spindler

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: German
• Weight: 158 KB
• Volume: 89
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200690173

✦ Synopsis

Abstract

The two diphosphine ligands (R~p~,R~p~)‐ and (S~p~,S~p~)‐bis[2‐(diphenylphospino)ferrocenyl]methane, (R~p~,R~p~)‐ and (S~p~,S~p~)‐1, resp., were prepared in six steps from (S)‐ and (R)‐ferrocenyl tolyl sulfoxide, respectively (Scheme). In the solid state, both the diborane complex (R~p~,R~p~)‐1 ⋅ (BH~3~)~2~ and the palladium dichloride complex [PdCl~2~((R~p~,R~p~)‐1)] were found to adopt C~2~‐pseudosymmetric structures according to X‐ray analyses (Figs. 2 and 3). In the Rh‐ and Ru‐catalyzed hydrogenation of selected alkenes and ketones in the presence of the new ligands, enantioselectivities of up to 55% ee were obtained.