Highly enantioselective copper-catalyzed allylic alkylation with atropos phosphoramidites bearing a D2-symmetric biphenyl backbone

A novel class of atropos dibridged biphenyl phosphoramidites bearing a D-2-symmetric biphenyl backbone was prepared and applied as chiral ligands in the copper-catalyzed allylic alkylation with Grignard reagent. The alkylation products were obtained in quantitative yields with high regioselectivities up to 94:6 of S(N)2'/S(N)2 ratio and enantiomeric excesses up to 91.1% for S(N)2' products. The unique D-2-symmetric backbone ligands have the advantages of easy preparation and sufficient reusability of their key intermediates from the undesired isomers. (C) 2010 Elsevier Ltd. All rights reserved.