Phase Transfer Activation of Fluorous Analogs of Grubbs’ Second-Generation Catalyst: Ring-Opening Metathesis Polymerization

Fluorine-containing ruthenium-based olefin metathesis catalysts

The review summarizes literature data on the methods for the introduction of fluorine atoms and fluoralkyl groups into different ligands to construct metathesis-active ruthenium carbene complexes. It also analyzes the influence of fluorinated ligands on the catalytic activity of the complexes. The choice, structure and positions of fluorinated substituents in NHC ligands are generally dictated by the desire to increase the electrophilicity of the ruthenium atom due to the electron-withdrawing effect of fluorine atoms and fluoroalkyl groups, resulting, as a rule, in an increase in the activity of the ruthenium complex. In catalysts with unsymmetrical fluorine-containing NHC ligands, there is a possibility of additional Ru–F coordination, making the complexes much more stable and, consequently, more active. The presence of fluorine in chelating alkylidene ligands provides an increase in the catalyst initiation rate due to a weakening of the ruthenium – heteroatom bond. Besides, the introduction of polyfluoroalkyl groups into ligands solves the problem of catalyst recovery using fluorous biphasic systems for reuse.

The bibliography includes 172 references.

Synthesis and supramolecular assembly of fluorinated biogenic amine recognition host polymers

Fluorine functionalized biogenic amine carrier polymers.

Perfluorinated phosphine and hybrid P–O ligands for Pd catalysed C–C bond forming reactions in solution and on Teflon supports

The synthesis of two types of phosphine ligands that feature perfluorinated ponytails is reported. A bidentate (RfCH₂CH₂)₂PCH₂CH₂P(CH₂CH₂Rf)₂ (Rf = CF₃(CF₂)_n; n = 5, 7) and an alkoxyphosphine made by ring opening a fluorous epoxide, RfCH₂CH(OH)CH₂PR₂ (Rf = CF₃(CF₂)₇), have been prepared and spectroscopically characterised. The electronic effects of the fluorous chains have been elucidated from either the ¹J_Pt–P or ¹J_P–Se coupling constants in Pt(ii) or phosphine selenide compounds. Whilst the bidentate phosphines do not give stable or active Pd catalysts, the hybrid ligand does allow Susuki, Heck and Sonogashira catalysis to be demonstrated with low catalyst loadings and good turnovers. Whilst a fluorous extraction methodology does not give good performance, the ligand can be adsorbed onto Teflon tape and for the Suzuki cross coupling reaction the catalytic system can be run 6 times before activity drops and this has been traced to oxidation of the ligand. Additionally the crystal structure of the hybrid phosphine oxide is reported and the non-covalent interactions discussed.

Phosphine ligands containing a perfluorous ponytail can be sorbed onto Teflon tape and used as ligands for C–C cross coupling reactions with little leaching.

Supported Catalysts Useful in Ring-Closing Metathesis, Cross Metathesis, and Ring-Opening Metathesis Polymerization

Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. This review highlights some of the history of efforts to address these problems, first discussing the problem in the context of reactions like ring-closing metathesis and cross metathesis catalysis used in the synthesis of low molecular weight compounds. It then discusses in more detail progress in dealing with these issues in ring opening metathesis polymerization chemistry. Such approaches depend on a biphasic solid/liquid or liquid separation and can use either always biphasic or sometimes biphasic systems and approaches to this problem using insoluble inorganic supports, insoluble crosslinked polymeric organic supports, soluble polymeric supports, ionic liquids and fluorous phases are discussed.

Synthesis and applications of fluorous phosphines

The synthesis, some of the properties and the applications of fluorous phosphines in biphasic, organometallic and organo-catalysis were reviewed.

ROMP of acetoxy-substituted dicyclopentadiene to a linear polymer with a high Tg

The acetoxy group was introduced to polydicyclopentadiene via ROMP of acetoxy-substituted dicyclopentadiene resulting in a linear polydicyclopentadiene derivative with high T_g.

Liquid/solid phase transfer activation of Grubbs-type alkene metathesis catalysts; application of silver salts of sulfonated polystyrene

An analog of Grubbs' second generation catalyst with a tetralkylammonium chloride containing phosphine exhibits faster rates in the presence of polystyrene-SO₃Ag.