TY - JOUR
AU - Maschmeyer, Thomas
AB - A new Brønsted acidic aluminosilicate, AlTUD‐1, with ideal characteristics for catalyst immobilisation (mesoporous structure, high surface area, and high Altetrahedral/Si ratio), was used successfully for the noncovalent anchoring of two well‐established asymmetric hydrogenation catalysts: [RhI(cod){(R,R)‐MeDuPHOS}]BF4 (1) and [RhI(cod){(S,S)‐DiPAMP}]BF4 (2). The new heterogeneous catalysts, 1‐AlTUD‐1 and 2‐AlTUD‐1, prepared by a straightforward ion‐exchange procedure, were highly active and selective in the asymmetric reduction of dimethyl itaconate (3) and methyl 2‐acetamidoacrylate (4), giving enantiomeric excesses of up to >98 %. The catalysts showed similar behaviour to their homogeneous counterparts. Catalyst 2‐AlTUD‐1 could be re‐used multiple times without loss of enantioselectivity or activity. Leaching of Rh showed a significant dependence on the polarity of the solvent in which the catalysis was performed. By applying tert‐butylmethyl ether (MTBE) as solvent, the loss of Rh could be reduced to <0.1 %. The solvent also had a noteworthy effect on the enantioselectivity in the hydrogenation of 4 (an effect not seen with 3 as substrate), that is, in MeOH the ee was 92 %, in MTBE it dropped to 26 % when using 2‐AlTUD‐1 as catalyst.
TI - Noncovalent Anchoring of Asymmetric Hydrogenation Catalysts on a New Mesoporous Aluminosilicate: Application and Solvent Effects
JF - Chemistry - A European Journal
DO - 10.1002/chem.200400528
DA - 2005-07-19
UR - https://www.deepdyve.com/lp/wiley/noncovalent-anchoring-of-asymmetric-hydrogenation-catalysts-on-a-new-7EVr3R6KMo
SP - 5829
EP - 5835
VL - 10
IS - 22
DP - DeepDyve
ER -