Immobilized DMAP Derivatives Rivaling Homogeneous DMAP

Significance

Polymer-supported DMAP derivatives were synthesized and found to exceed the catalytic activity of commercially available DMAP-PS eightfold for acylation. Thus, the reaction of (rac)-DMAP derivative 1 with BH₃SMe₂ gave borate 2, which was reacted with (5-iodo-1-pentynyl)trimethylsilane and washed with HCl to afford compound 3. After removal of the TMS group, the resulting acetylene 4 was treated with azide-substituted Merrifield resin to give the [3+2]-­cycloaddition product, polystyrene-supported DMAP 5, with a loading of 1.30 mmol/g (N). The acylation of 1-ethynylcyclohexanol (6a) with acetic anhydride was carried out in the presence of polymeric catalyst 5 (10 mol% N) to give 7a in 100% yield.