A family of cis-macrocyclic diphosphines: modular, stereoselective synthesis and application in catalytic CO₂/ethylene Coupling

• Main Authors: Beetstra, Dirk (Author), Al-Nezari, Abdulaziz (Author), Al-Bahily, Khalid (Author), Knopf, Ioana (Contributor), Tofan, Daniel (Contributor), Cummins, Christopher C (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Chemistry (Contributor)
• Format: Article
• Language: English
• Published: Royal Society of Chemistry (RSC), 2018-01-22T15:18:00Z.
• Subjects: Article
• Online Access: Get fulltext

 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 P₂(dmb)₂ , produced phosphino-phosphonium salts [R-P₂(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 Cy₂-DPC was synthesized in 74% yield from the dichlorodiphosphine Cl₂P₂(dmb)₂. As a first application, these cis-macrocyclic diphosphines were used as ligands in the nickel-catalyzed synthesis of acrylate from CO₂ and ethylene, for which they showed promising catalytic activity.