An insoluble polymer-bound phosphoramidite for the copper-catalysed enantioselective 1,4-addition of ZnEt2 to 2-cyclohexenone

The preparation of a chiral phosphoramidite ligand anchored to a Merrifield resin has been studied and its use in the copper-catalysed heterogeneous enantioselective conjugate addition of ZnEt2 to 2-cyclohexenone investigated. The insoluble polymer bound ligand could be recovered quantitatively by filtration, affording e.e. values in the range 65-84%, in the course of successive recycle runs. (C) 2003 Elsevier Ltd. All rights reserved.