Catalysts amine-phenolate

SCHEME 2.13 Amine-phenolate catalysts for living polymerization of 1-hexene (R = Bu) and 4-methyl-1-pentene (R = Cl). 

Acetoiicetyliition Reactions. The best known and commercially most important reaction of diketene is the aceto acetylation of nucleophiles to give derivatives of acetoacetic acid (Fig. 2) (1,5,6). A wide variety of substances with acidic hydrogens can be acetoacetylated. This includes alcohols, amines, phenols, thiols, carboxyHc acids, amides, ureas, thioureas, urethanes, and sulfonamides. Where more than one functional group is present, ring closure often follows aceto acetylation, giving access to a variety of heterocycHc compounds. These reactions often require catalysts in the form of tertiary amines, acids, and mercury salts. Acetoacetate esters and acetoacetamides are the most important industrial intermediates prepared from diketene. 

Epoxides can react with alcohols via acidic or basic catalysed reaction mechanisms. However, since both strong acids and bases will degrade the cell wall polymers of wood, the reaction is usually catalysed via the use of amines, which are more strongly nucleophilic than the OH group. For example, whereas the production of epoxy-phenolic resins requires temperatures in the region of 180-205 °C, reaction between epoxides and primary or secondary amines takes place at 15 °C (Turner, 1967). Reaction of epoxides with wood often involves the use of tertiary amines as catalysts (Sherman etal., 1980). The sapwood is more reactive towards epoxides than heartwood (Ahmad and Harun, 1992). 

Regiocontrol Although Michael additions to [Os]-phenol occur selectively at C4, addition at C2 is thermodynamically favored for phenol complexes that are substituted at C4. For C4-substituted phenol complexes, the regiochemistry can be controlled by varying the time, temperature, and catalyst (Figure 6) [29]. Additions of MVK to the estradiol complex 90 and the p-cresol 94 at —40 °C in the presence of an amine base catalyst result in regioselective C4 alkylation in high yields (91 and 95). However, when this reaction is performed at room temperature in the presence of a Zn2+ co-catalyst, the Michael acceptor adds at C2 to afford... 

Besides 11-18, several other formylation methods are known." In one of these, dichloromethyl methyl ether formylates aromatic rings with Friedel-Crafts catalysts." The ArCHClOMe compound is probably an intermediate. Orthoformates have also been used." In another method, aromatic rings are formylated with formyl fluoride HCOF and BF3." Unlike formyl chloride, formyl fluoride is stable enough for this purpose. This reaction was successful for benzene, alkylbenzenes, PhCl, PhBr, and naphthalene. Phenols can be regioselectively formylated in the ortho position in high yields by treatment with 2 equivalents of paraformaldehyde in aprotic solvents in the presence of SnCLj and a tertiary amine." Phenols have also been formylated indirectly by conversion to the aryllithium reagent followed by treatment with V-formyl piperidine." See also the indirect method mentioned at 11-23. 

Although the telomerization of dienes in a two-phase system has been intensively investigated with compounds containing active hydrogen such as alcohols, amines, phenols, acids, etc., the selective and productive telomerization of butadiene continues to be a challenge. It is only recently that primary octadi-enylamines have been obtained with selectivity up to 88% in the telomerization of butadiene with ammonia using a two-phase toluene/water system and Pd(OAc)2/tppts as the catalyst [Eq. (23)] [125]. 

Substitution of aromatic halides or recrystes in the synthesis of diaryls, diaryl ethers, diaryl amines, phenols etc catalyzed by Cu and other catalysts... 

ISOBUTYL METHACRYLATE (97-86-9) Forms explosive mixture with air (flash point 112°F/44°C). Unless inhibited [25 ppm hydroquinone monomethyl ether, 10 ppm p-methoxy phenol (MEHQ) are recommended], forms unstable peroxides elevated temperatures may cause polymerization. Incompatible with strong acids, aliphatic amines, alkanolamines, catalysts, nitrates, strong oxidizers. 

Most osmium complexes of phenols [26,44], anilines [24,45], and anisoles [23, 46,47] undergo electrophilic addition with a high regiochemical preference for para addition. While electrophilic additions to phenol complexes are typically carried out in the presence of an amine base catalyst, the other two classes generally require a mild Lewis or Bronsted acid to promote the reaction. The primary advantage of the less activated arenes is that the 4H-arenium species resulting from electrophilic addition are more reactive toward nucleophilic addition reactions (see below). 

The various aspects of oxidative polymerization of phenols have been thoroughly reviewed. Most commonly PPEs are produced by the self-con-densation of a monovalent phenol in the presence of oxygen and a metal-amine-complex catalyst. Manganese, copper and cobalt can be used as the metal in the catalyst. Cu+ is most commonly utilized. For example, the preparation of the catalyst can be achieved by stirring cuprous bromide and di-n-butyl amine in toluene. ... 

The copper halide/amine (pyridine) catalyst system promotes the conversion of phenol to o-benzoquinone via intermediate formation of a copper-catecholato species [107,108]. The proposed hydroxylation mechanism involves initial complexation of copper(I) with phenolate, followed by reaction with dioxygen (Scheme 6). 

Although the anhydride may be used on its own, the acylation reactions go most smoothly and quickly in a solvent and with a catalyst. The precise nature of the solvent is not important, but it is common to use a solvent such as acetonitrile which can act in both capacities. The following conditions are satisfactory for phenols, amines, phenolic amines and alcohols. 

The allylic alkylation with weak nucleophiles employing nickel catalysts is generally not as efficient as the corresponding palladium-catalyzed methods. However, allylic acetates, allyl phenyl ethers, and allylic carbonates undergo efficient couplings with amines, phenols, and malonates in the presence of nickel(O) catalysts (Scheme 25). ... 

Similar results are observed in model studies if phenyl chloroformate is added to an interfacial reaction mixture containing caustic and a tertiary amine followed by systematic quenching of samples taken over the course of the reaction with a secondary amine. Diphenyl carbonate is produced to the exclusion of phenol or the phenyl dialkyl urethane which results upon quenching with amine. If phase-transfer catalysts are used instead of tertiary amines, then diphenyl carbonate is not produced and urethanes are the major product formed upon quenching samples with the secondary amine. However, if equal molar amounts of phenyl chloroformate and a phenol are added to an interfacial mixture containing either a tertiary amine or a phase-transfer catalyst, then diphenyl carbonate is produced very rapidly. Thus, at least the hydrolysis portion of the cyclization reaction requires a tertiary amine acylation catalyst. 

The enzymatic polymerisation of phenol catalysed by EIRE was efficiently performed in phosphate buffer (pFI = 7.0) containing sodium dodecyl sulfate SDS, an environment-friendly system [171]. The obtained phenol polymer is partly soluble in common solvents, such as acetone, THE and DMF. IR analysis shows that the polymer is composed of phenylene and oxyphenylene units. The functionalisation of the phenol polymer was performed by reacting with epoxy chloropropane and triethylene-tetramine, the insoluble aminated phenol polymer was then obtained. The aminated phenol polymer was adopted as a carrier to prepare a novel supported palladium catalyst (PP-N-Pd) for the Heck reaction. 

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