Polystyrene-Supported TRIP: A Highly Recyclable Catalyst for Batch and Flow Enantioselective Allylation of Aldehydes

The widely applicable TRIP phosphoric acid catalyst has been immobilized on polystyrene using a copolymerization-based strate-gy. The resin (PS-TRIP) has proven highly active and enantioselective in the asymmetric allylboration of aldehyes. Moreover, it has shown to be extremely robust, as it can be reused for 18 times, after which it still retained its activity. Finally, to further prove the benefits of the immobilization, a continuous flow experiment spanning 28 h has been carried out with very high yields and ee’s.