Supported Phosphines

In a similar fashion, efforts for the development and application of supported phosphines as scavengers to remove various electrophiles have been reported. Reports demonstrate the diversity of resin-tags used, and their applications as both 

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The use of water-soluble reagents and catalysts allows reactions to be performed in aqueous buffered solutions. PEG-supported triarylphos-phine has been used in a Wittig reaction under mildly basic aqueous conditions (Eq. 8.115). The PEG-supported phosphine oxide byproduct can be easily recovered and reduced by alane to regenerate the starting reagent for reuse.312 The aqueous Wittig reaction has also been used in... 

Olefinations using a solid-supported triphenylphosphine were accomplished within 5 min of microwave heating at 150 °C using potassium carbonate as the base and methanol as the solvent (Scheme 7.96). A variety of aldehydes and organic halides were studied with the solid-supported phosphine, yielding the corresponding alkenes in excellent purities. 

In 1993 Bergbreiter prepared two soluble polymer-supported phosphines that exhibited an inverse temperature-dependent solubility in water [52]. Although PEG-supported phosphine undergoes a phase-separation from water at 95-100 °C, the PEO-poly(propylene oxide)-PEO supported catalyst was superior as it is soluble at low temperatures and phase-separates at a more practical 40-50 °C. Treatment of a diphenylphosphinoethyl-terminated PEO-PPO-PEO triblock copolymer... 

For this complex, molecular chemistry does not adequately model the surface reactivity and the latter is strongly influenced by the presence of surface hydroxyl groups [22]. The organometallic fragments immobilized on silica have been reacted with trimethylphosphine to afford different silica-supported phosphine complexes of rhodium. The course of the reaction depends strongly on the hydroxyl content of the silica surface [23] (Scheme 7.2). 

The failure to observe any leaching could either indicate that the initial dissociation of the supported phosphine-rhodium(I) bond does not occur or that having been displaced from one site within the support the rhodium subsequently binds to another site. This latter possibility would not lead to any significant leaching in experiments where the catalyst was shaken with the reactants, although, if the reactants were passed through a bed or column of catalyst, leaching should then be observable. 

Organometallic complex catalysts have been removed from reaction mixtures with solid-supported phosphines as well as other ligands to facilitate reagent handling and product purification. Alternatively, Leadbeater28... 

Polybutenes, polymerization with metallocenes, 4, 1078 Poly(4-/< r/-butylstyrene) supports, phosphine-derived, for Pd complexes, 12, 679... 

Sulfonamides may be directly synthesized from sulfonic acid salts by treatment with triphenylphosphine ditriflate followed by an amine <2004JA1024>. This procedure, that avoids the generation of sulfonic acids, converts sulfonic acid salt 129 to sulfonamide 130 in 81% yield (Equation 92). Problems associated with the removal of triphenylphosphine oxide by-products can be alleviated by performing the reaction with polystyrene-supported phosphine. 

Bis(phosphino)amines (208)-(211) were readily prepared by condensation of Ph2PCl and the appropriate secondary amine in diethyl ether, tetrahydrofuran, dichloromethane, or benzene, with triethylamine as base.454-457 Polymer-supported phosphine-phosphino(amines) (212) have also been reported.458 Hersh and co-workers have described a novel series of bis(p-toluenesulfonylamino) phosphines (213) and (214) from bis(dichlorophosphino) starting materials and A,vV -(ditoluenesul-fonyl)-l, 2-diaminoethane.459... 

CH30C6H4Br, f-BuONa, Pd(OAc)2, polymer supported phosphine ligand, toluene, SOT, 15-20h, 84% yield. ... 

Two types of supported phosphine polymers were prepared. Phosphinopyrrolidine-containing polymers were prepared by copolymerizing 2 with acrylates 3a-c and... 

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