BINOL-Based Ditopic Diphosphite Ligands – Synthesis, Evaluation and Regioselectivity Optimization of Catalytic Hydroformylation by 2³ Factorial Design

Title:BINOL-Based Ditopic Diphosphite Ligands – Synthesis, Evaluation and Regioselectivity Optimization of Catalytic Hydroformylation by 2³ Factorial Design

Volume: 11 Issue: 2

Author(s): Andreia F. Peixoto, Artur R. Abreu, Ana R. Almeida, Angela Neves, Paulo E. Abreu, Maria J.S.M. Moreno, Juan C. Bayon, Alberto A.C.C. Pais and Mariette M. Pereira

Affiliation:

Keywords: BINOL, diphosphite, ditopic, hydroformylation, rhodium, regioselectivity, Lithium ion.

Abstract: 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.

Cite this article as:

Peixoto F. Andreia, Abreu R. Artur, Almeida R. Ana, Neves Angela, Abreu E. Paulo, Moreno J.S.M. Maria, Bayon C. Juan, Pais A.C.C. Alberto and Pereira M. Mariette, BINOL-Based Ditopic Diphosphite Ligands – Synthesis, Evaluation and Regioselectivity Optimization of Catalytic Hydroformylation by 2³ Factorial Design, Current Organic Synthesis 2014; 11 (2) . https://dx.doi.org/10.2174/15701794113106660072