A Recyclable Catalyst for the Synthesis of 1,5-Benzodiazepine Derivatives: Polymer-Supported Ytterbium Perfluorooctanesulfonate [Yb(OPf)3]

Amberlyst-21, a kind of well-known and cheap polymeric material, was treated with ytterbium perfluorooctanesulfonate [Yb(OPf)(3)] giving a reagent with a ytterbium loading of 1.34 (wt %). The polymer-supported fluorous ytterbium catalyses the highly efficient synthesis of 1,5-benzodiazepine derivatives. The catalyst can be recovered by simple filtration under fluorous-solvent-free conditions and used again without a significant loss of catalytic activity.