Synthesis and characterization of a chiral, aza-15-crown-5-functionalized ferrocenyldiphosphine ligand for asymmetric catalysis

Citation
Cr. Landis et al., Synthesis and characterization of a chiral, aza-15-crown-5-functionalized ferrocenyldiphosphine ligand for asymmetric catalysis, ORGANOMETAL, 19(6), 2000, pp. 994-1002
Citations number
41
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
ORGANOMETALLICS
ISSN journal
02767333 → ACNP
Volume
19
Issue
6
Year of publication
2000
Pages
994 - 1002
Database
ISI
SICI code
0276-7333(20000320)19:6<994:SACOAC>2.0.ZU;2-Z
Abstract
A chiral ferrocenyldiphosphine ligand that is functionalized with an aza cr own ether, (S)1-[(R)-1',2-bis(diphenylphosphino)ferrocenyl]ethyl-1-aza-2,3- benzo-15-crown-5 (1), has been synthesized. Both the resolved and racemic l igands react rapidly with Pt(II) precursors to form stable metal-ligand add ucts; the complexes PtMeI(rac-1) and PtMe2(rac-1) have been characterized c rystallographically. Reaction of rac-1 with [Rh(NBD)(2)]OTf yields [Rh(NBD) (rac-1)]OTf. The three-dimensional solution structure of [Rh(NBD)(rac-1)]OT f has been determined by NOESY experiments and analysis using the two-dimen sional conformer population analysis algorithm (2DCPA). The NOESY data reve al a rapid, pairwise chemical exchange between vinyl protons. The complex [ Rh(NBD)(rac-1)]OTf is a catalyst precursor for hydrogenation reactions. How ever, we demonstrate that the lability of the aza crown ether may limit the ability of these catalysts to control selectivity via secondary interactio ns.