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Chiral (Diphosphonite)platinum Complexes in Asymmetric Hydroformylation
Author(s) -
van Duren Ruben,
Cornelissen Leandra L. J. M.,
van der Vlugt Jarl Ivar,
Huijbers Jeroen P. J.,
Mills Allison M.,
Spek Anthony L.,
Müller Christian,
Vogt Dieter
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690156
Subject(s) - hydroformylation , chemistry , regioselectivity , xanthene , ligand (biochemistry) , styrene , platinum , stereochemistry , medicinal chemistry , triphenylphosphine , vinyl acetate , rhodium , nuclear magnetic resonance spectroscopy , crystal structure , metal , crystallography , catalysis , photochemistry , organic chemistry , copolymer , biochemistry , polymer , receptor
The chiral diphosphonite ligand (11b R ,11′b R )‐4,4′‐(9,9‐dimethyl‐9 H ‐xanthene‐4,5‐diyl)bis[dinaphtho[2,1‐ d :1′,2′‐ f ][1,3,2]dioxaphosphepin] (( R,R )‐XantBino; ( R )‐ 1 ), based on a rigid xanthene backbone, was applied in the Pt/Sn‐catalyzed hydroformylation of styrene ( 4a ), 4‐methylstyrene ( 4b ), vinyl acetate ( 4c ), and allyl acetate ( 4d ), by using a Pt/Sn ratio of 1 : 1. High ee of up to 80% were observed, along with good regioselectivities towards the desired branched aldehydes. For styrene, an interesting inversion in the stereoselection process was observed at elevated temperatures, and a mechanism is proposed considering the temperature dependence of the regioselectivity. The complex [PtCl 2 {( S,S )‐XantBino}] (( S )‐ 2 ) was characterized by X‐ray crystal‐structure analysis, revealing an unusual out‐of‐plane ligand coordination of the metal fragment. The complex [PtCl(SnCl 3 ){( R,R )‐XantBino}] (( R )‐ 3 ) was characterized by means of 31 P‐NMR spectroscopy.