Synthesis and characterization of new (N‐diphenylphosphino)‐isopropylanilines and their complexes: crystal structure of (Ph2P S)NHC6H44CH(CH3)2 and catalytic activity of palladium(II) complexes in the Heck and Suzuki cross‐coupling reactions

Abstract

AbstractThree new (N‐diphenylphosphino)‐isopropylanilines, having isopropyl substituent at the carbon 2‐ (1) 4‐ (2) or 2,6‐ (3) were prepared from the aminolysis of chlorodiphenylphosphine with 2‐isopropylaniline, 4‐isopropylaniline or 2,6‐diisopropylaniline, respectively, under anaerobic conditions. Oxidation of 1,2 and 3 with aqueous hydrogen peroxide, elemental sulfur or gray selenium gave the corresponding oxides, sulfides and selenides (Ph2PE)NHC6H42‐CH(CH3)2, (Ph2PE)NHC6H44‐CH(CH3)2 and (Ph2PE)NHC6H42,6‐{CH(CH3)2}2, where E = O, S, or Se, respectively. The reaction of [M(cod)Cl2] (M = Pd, Pt; cod = 1,5‐cyclooctadiene) with two equivalents of 1,2 or 3 yields the corresponding monodendate complexes [M((Ph2P)NHC6H42‐CH(CH3)2)2Cl2], M = Pd 1d, M = Pt 1e, [M((Ph2P)NHC6H44‐CH(CH3)2)2Cl2], M = Pd 2d, M = Pt 2e and [M((Ph2P)NHC6H42,6‐(CH(CH3)2)2)2Cl2], M = Pd 3d, M = Pt 3e, respectively. All the compounds were isolated as analytically pure substances and characterized by NMR, IR spectroscopy and elemental analysis. Furthermore, representative solid‐state structure of [(Ph2PS)NHC6H44‐CH(CH3)2] (2b) was determined using single crystal X‐ray diffraction technique. The complexes 1d–3d were tested and found to be highly active catalysts in the Suzuki coupling and Heck reaction, affording biphenyls and stilbenes, respectively. Copyright © 2009 John Wiley & Sons, Ltd.