A family of cis-macrocyclic diphosphines: modular, stereoselective synthesis and application in catalytic CO2/ethylene coupling† †Electronic supplementary information (ESI) available: Full experimental, crystallographic and spectroscopic data. CCDC 1477899–1477902. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc03614g Click here for additional data file. Click here for additional data file

• Published in: Chemical science (Cambridge) 2016-10, Vol.8 (2), p.1463-1468
• Main Authors: Knopf, Ioana, Tofan, Daniel, Beetstra, Dirk, Al-Nezari, Abdulaziz, Al-Bahily, Khalid, Cummins, Christopher C.
• Format: Article
• Language: English
• Subjects: Chemistry
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c6sc03614g

The stereoselective synthesis of a family of cis -macrocyclic diphosphines was achieved in only three steps from white phosphorus and commercial materials. These new ligands showed activity in the nickel-catalyzed coupling of CO 2 and ethylene. A family of cis -macrocyclic diphosphines was prepared in just three steps from white phosphorus and commercial materials using a modular synthetic approach. Alkylation of bicyclic diphosphane 3,4,8,9-tetramethyl-1,6-diphosphabicyclo(4.4.0)deca-3,8-diene, or P 2 (dmb) 2 , produced phosphino-phosphonium salts [R-P 2 (dmb) 2 ]X, where R is methyl, benzyl and isobutyl, in yields of 90–96%. Treatment of these salts with organolithium or Grignard reagents yielded symmetric and unsymmetric macrocyclic diphosphines of the form cis -1-R-6-R′-3,4,8,9-tetramethyl-2,5,7,10-tetrahydro-1,6-DiPhospheCine, or R,R′-DPC, in which R′ is methyl, cyclohexyl, phenyl or mesityl, in yields of 46–94%. Alternatively, symmetric diphosphine Cy 2 -DPC was synthesized in 74% yield from the dichlorodiphosphine Cl 2 P 2 (dmb) 2 . As a first application, these cis -macrocyclic diphosphines were used as ligands in the nickel-catalyzed synthesis of acrylate from CO 2 and ethylene, for which they showed promising catalytic activity.