TY - JOUR
T1 - Rh(I) coordination chemistry of hexacationic Dendriphos ligands and their application in hydroformylation catalysis
AU - Snelders, D.J.M.
AU - Kunna, K.
AU - Müller, C.
AU - Vogt, D.
AU - Koten, G. V.
AU - Klein Gebbink, R.J.M.
PY - 2010
Y1 - 2010
N2 - The coordination chemistry of hexacationic Dendriphos ligands L* with respect to Rh(I), as well as their
application in Rh-catalyzed hydroformylation reactions, is described. Complexes of the type
RhCl(CO)(L*)2 were synthesized and characterized. The results show that Dendriphos ligands are weaker
r-donors and/or stronger p-acceptors compared to PPh3. The reaction of L* with [Rh(cod)2]BF4 in MeCN
afforded monophosphine-Rh(I) complexes of the type Rh(cod)(MeCN)(L*), which points to the tendency
of these ligands to form coordinatively unsaturated metal complexes. The catalytic performance of Dendriphos
ligands in the Rh-catalyzed hydroformylation appeared to be dominated by steric effects arising
from the large dendritic shells of these ligands. Furthermore, the possibility of tuning the catalytic
activity and selectivity of the catalytic species, by changing the six counteranions of the hexacationic
Dendriphos ligand, has been investigated. Changing the anions from BF4
to the chiral anions camphorsulphonate
or D-Trisphat did not render the hydroformylation reaction of styrene enantioselective,
albeit small changes in its regioselectivity were observed.
AB - The coordination chemistry of hexacationic Dendriphos ligands L* with respect to Rh(I), as well as their
application in Rh-catalyzed hydroformylation reactions, is described. Complexes of the type
RhCl(CO)(L*)2 were synthesized and characterized. The results show that Dendriphos ligands are weaker
r-donors and/or stronger p-acceptors compared to PPh3. The reaction of L* with [Rh(cod)2]BF4 in MeCN
afforded monophosphine-Rh(I) complexes of the type Rh(cod)(MeCN)(L*), which points to the tendency
of these ligands to form coordinatively unsaturated metal complexes. The catalytic performance of Dendriphos
ligands in the Rh-catalyzed hydroformylation appeared to be dominated by steric effects arising
from the large dendritic shells of these ligands. Furthermore, the possibility of tuning the catalytic
activity and selectivity of the catalytic species, by changing the six counteranions of the hexacationic
Dendriphos ligand, has been investigated. Changing the anions from BF4
to the chiral anions camphorsulphonate
or D-Trisphat did not render the hydroformylation reaction of styrene enantioselective,
albeit small changes in its regioselectivity were observed.
U2 - 10.1016/j.tetasy.2010.04.037
DO - 10.1016/j.tetasy.2010.04.037
M3 - Article
SN - 0957-4166
VL - 21
SP - 1411
EP - 1420
JO - Tetrahedron-Asymmetry
JF - Tetrahedron-Asymmetry
IS - 11-12
ER -