Asymmetric hydrogenation of methyl pyruvate in the continuous gas phase using Supported Ionic Liquid Phase (SILP) catalysis

- The asymmetric reduction of the α-keto ester methyl pyruvate in continuous-flow, gas phase reaction using Supported Ionic Liquid Phase (SILP) catalysis is demonstrated.
- Different support materials, ligands and ionic liquids were screened to identify an optimized Ru-based SILP catalyst.
- With Ru-BINAP dissolved in the ionic liquids 3-hydroxypropylpyridinium bis(trifluoromethylsulfonyl)imide on silica 100 a stable catalyst performance could be obtained for more than 50 h time-on-stream.
- At 95 °C and with a residence time in the reactor of less than 3 s a stable product yield of 80-84% was obtained with moderate but stable enantiomeric excess of 26-30%.