MaxPHOS Ligand: PH/NH Tautomerism and Rhodium‐ Catalyzed Asymmetric Hydrogenations. Issue 4 (3rd March 2014)

• Record Type: Journal Article
• Authors: Cristóbal‐Lecina, Edgar; Etayo, Pablo; Doran, Séan; Revés, Marc; Martín‐Gago, Pablo; Grabulosa, Arnald; Costantino, Andrea R.; Vidal‐Ferran, Anton; Riera, Antoni; Verdaguer, Xavier
• Is Part Of: Advanced synthesis & catalysis. Volume 356:Issue 4(2014)
• Page Start: 795
• Page End: 804
• Publication Date: 2014-03-03
• Subjects: Catalysis -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Chemistry -- Periodicals; Chemistry, Technical -- Periodicals; Chemistry -- Periodicals; Catalysis -- Periodicals; Technology, Pharmaceutical -- Periodicals; 547.2
• DOI: 10.1002/adsc.201300662
• Languages: English
• ISSNs: 1615-4150

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>MaxPHOS is an active and robust P‐stereogenic ligand for asymmetric catalysis. The presence of an NH bridge between the two phosphine moieties allows the NH/PH tautomerism to take place. The neutral ligand, in which the NH form predominates, is an air‐sensitive compound. However, protonation of MaxPHOS leads to the stable PH form of the ligand, in which the overall positive charge is distributed on both P centers. This protonation turns the MaxPHOS⋅HBF₄ salt <bold>3</bold> into an air‐stable compound both in the solid state and in solution. The salt <bold>3</bold> is also a convenient precursor for the preparation of rhodium(I) complexes by direct ligand exchange with the complex [Rh(acac)(cod)]. Finally, the corresponding rhodium(I)‐MaxPHOS complex was tested in the asymmetric hydrogenation of a wide range of substrates. The complex proved to be a highly selective and robust system in these reactions.</p> <p> <boxed-text content-type="graphic" position="anchor" orientation="portrait"> <graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgg4sx601j9" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /> </boxed-text> </p> </abstract>