Eu(fod)3-catalyzed solid-phase [4+2] heterocycloadditions: an efficient asymmetric process in catalyst-recycling conditions

Under Eu(fod)3-catalyzed conditions, the endo-selective hetero Diels–Alder reaction of (S)-(+)-O-vinyl mandelate with Wang-supported benzylidenepyruvate occurred with a 93/7 facial selectivity that compares well with those observed in solution. In addition, the solid-phase sequence allowed an unprecedented reuse of the catalyst in the presence of excess dienophile in solution.