TY - JOUR
T1 - Chiral (Diphosphonite)platinum complexes in asymmetric hydroformylation
AU - Duren, van, R.
AU - Cornelissen, L.L.J.M.
AU - Vlugt, van der, J.I.
AU - Huijbers, J.P.J.
AU - Mills, A.M.
AU - Spek, A.L.
AU - Müller, C.
AU - Vogt, D.
PY - 2006
Y1 - 2006
N2 - The chiral diphosphonite ligand (11bR,11bR)-4,4-(9,9-dimethyl-9H-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 [PtCl2{(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(SnCl3){(R,R)-XantBino}] ((R)-3) was characterized by means of 31P-NMR spectroscopy.
AB - The chiral diphosphonite ligand (11bR,11bR)-4,4-(9,9-dimethyl-9H-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 [PtCl2{(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(SnCl3){(R,R)-XantBino}] ((R)-3) was characterized by means of 31P-NMR spectroscopy.
U2 - 10.1002/hlca.200690156
DO - 10.1002/hlca.200690156
M3 - Article
SN - 0018-019X
VL - 89
SP - 1547
EP - 1558
JO - Helvetica Chimica Acta
JF - Helvetica Chimica Acta
IS - 8
ER -