Synthesis of P‐Stereogenic Phosphoramidite and Phosphorodiamidite Ligands and Their Application in Asymmetric Catalysis. Issue 28 (12th August 2015)

• Record Type: Journal Article
• Authors: Schmitz, Christian; Leitner, Walter; Franciò, Giancarlo
• Is Part Of: European journal of organic chemistry. Issue 28(2015)
• Page Start: 6205
• Page End: 6230
• Publication Date: 2015-08-12
• Subjects: Asymmetric catalysis -- Ligand design -- P ligands -- P‐chirality -- Betti base; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201500767
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: A series of P ‐stereogenic monodentate phosphoramidite (PNO2 ) and phosphorodiamidite (PN2 O) ligands based on chiral Betti bases has been prepared by modular synthetic procedures. The chirality at the phosphorus can be controlled to a large extent by the synthetic route, leading to stereoselective access to single P‐epimers. The absolute configuration of the P‐atom was assigned by X‐ray diffraction analysis. The new ligands were evaluated in asymmetric catalysis and the influence of the exocyclic amine or alcohol moiety as well as the interplay between the P‐chirality and the stereocenters in the backbone were investigated. Enantioselectivities of up to 85 and 83 % ee were obtained in the Rh‐catalyzed hydrogenation of dimethyl itaconate and in the Pd‐catalyzed allylic amination of ( rac )‐( E )‐1, 3‐diphenylallyl acetate with benzylamine, respectively. In the Ni‐catalyzed hydrovinylation of styrene, ee values of up to 68 %, excellent chemoselectivities, and high activities (TOFav up to 3000 h –1 ) were achieved. Abstract : A series of phosphoramidite (R = OR) and phosphorodiamidite (R = NR2 ) ligands containing a stereogenic phosphorus atom has been synthesized from chiral Betti bases as amino alcohol building blocks. The new ligands have been applied in three different asymmetric metal‐catalyzed reactions, and the interplay between P ‐stereochemistry, structural features of R, and chirality at the backbone evaluated.