A Silica-Supported Yttrium Triflate Packed Bed Reactor for Continuous Flow Michael Addition of Indoles to Benzylidene Malonates

The catalytic properties of packed bed reactors filled with yttrium triflate immobilised onto functionalised silica have been tested in the Michael addition of indoles to benzylidene malonates under flow conditions, providing improved productivity over the batch conditions, a greater ease of recovery of the final products and a prolonged life of the catalyst. Noteworthy, the same catalytic reactor, after being used for five days, was employed to perform a different reaction, a stereoselective Diels Alder cycloaddition in flow, with a 24 times higher productivity compared to the in-batch reaction.