BINOL-based ditopic diphosphite ligands – synthesis, evaluation and regioselectivity optimization of catalytic hydroformylation by 23factorial design

Andreia F. Peixoto, Artur R. Abreu, Ana R. Almeida, Angela Neves, Paulo E. Abreu, Maria J.S.M. Moreno, Juan C. Bayón, Alberto A.C.C. Pais, Mariette M. Pereira

Research output: Contribution to journalArticleResearchpeer-review

5 Citations (Scopus)

Abstract

© 2014 Bentham Science Publishers. BINOL-based diphosphite ligands containing oxygen or nitrogen heteroatoms are currently a new class of promising ligands for homogeneous catalysis. Herein we present a useful strategy to synthesize ditopic (R)-BINOL-based diphosphites, containing pyridyl or propyl ether bridges between BINOL fragments in high isolated yields (50-92 %). Their rhodium complexes were evaluated in styrene hydroformylation, in which a moderate regioselectivity for the branched aldehyde was observed. The addition of a lithium salt led to a significant increase in the regioselectivity (25 %) for the branched aldehyde. This interesting observation has been rationalized based on a full two-level factorial design with 3 factors, including pressure, temperature and the Li/Rh ratio, using Rh/10 as model catalyst. The improvement of the regioselectivity in the presence of lithium salts has been interpreted through31PNMR spectroscopy and semiempirical PM6 computational studies.
Original languageEnglish
Pages (from-to)301-309
JournalCurrent Organic Synthesis
Volume11
Issue number2
DOIs
Publication statusPublished - 1 Jan 2014

Keywords

  • BINOL
  • Diphosphite
  • Ditopic
  • Hydroformylation
  • Lithium ion
  • Regioselectivity
  • Rhodium

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