The Synthesis of New HetPHOX Ligands and Their Application to the Intermolecular Asymmetric Heck Reaction

The synthesis of six members of the HetPHOX ligand class and the application of palladium complexes of these ligands to the intermolecular asymmetric Heck reaction is described. The tert‐leucinol‐derived ligands proved the most enantioselective, with palladium complexes of these ligands affording ee values of up to 96, 95 and 94 % in the phenylation, cyclohexenylation and naphthylation, respectively, of 2,3‐dihydrofuran. As an aid to the explanation of the observed selectivity a palladium complex of the most enantioselective ligand was prepared and an X‐ray crystal structure obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)