Palladium-Duphos structural and enantioselective hydroarylation chemistry

A series of Pd(II) complexes of 1,2-bis((2R,5R)-2,5-dimethylphospholano)benzene (MeDuphos; 1) have been prepared, and the solid-state structures for five of these, PdBr(p-CN-C6H4)(1), PdX(C6F5)(1) (X = Br, I), Pd(OAc)(2)(1), and [Pd(CH3CN)(2)(1)](PF6), have been determined by X-ray diffraction. Several of these complexes are catalyst precursors for the enantioselective hydroarylation of norbornene with PhX (X = Br, I, OTf). The maximum ee, 75%, is higher than the corresponding values previously reported for bidentate phosphine auxiliaries. NOESY NMR results show how complexed 1 interacts with the aryl ligand in PdBr(p-CN-C6H4)(1).