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Palladium, benzyl catalyst

Complexes of other metals are also capable of catalyzing useful carbonylation reactions under phase transfer conditions. For example, certain palladium(o) catalysts, like Co2(C0)g, can catalyze the carbonylation of benzylic halides to carboxylic acids. When applied to vinylic dibromides, unsaturated diacids or diynes were obtained, using Pd(diphos)2[diphos l,2-bis(diphenylphosphino)ethane] as the metal catalyst, benzyltriethylammonium chloride as the phase transfer agent, and t-amyl alcohol or benzene as the organic phase(18),... [Pg.12]

In order to obtain a commercially viable process it is necessary to racemize the unwanted amine enantiomer, preferably in situ in a so-called DKR. The paUadium-on-charcoal-catalyzed racemization of amines was first reported by Murahashi et al. [23] and was later combined with Upase-catalyzed acylation, to afford a DKR, by Reetz [24] and others [25]. We were able to achieve a DKR of a-methyl benzyl-amine by performing the hpase-catalyzed acylation in the presence of a palladium nanoparticle catalyst (Scheme 6.10). [Pg.117]

Deacetylation of (R) and (S), and hydrogenolytic removal of the benzyl groups in the presence of 10% palladium-carbon catalyst gave the desired optically pure 2-deoxy-2-(R- and S 3-hydro-... [Pg.279]

Carbonylation of benzyl chloride This reaction can be effected with cobalt carbonyl or a palladium(O) catalyst under phase-transfer conditions. CeCl3 promotes this phase-transfer process and also permits the use of nickel(II) cyanide as the... [Pg.72]

Debenzylation by reductive cleavage over palladium metal catalysts with molecular hydrogen has been widely utilized for many decades. A comprehensive review of the early literature on hydrogenolysis of benzyl groups emphasized the main applications and described a number of preparative procedures which are still frequently used, along with a wider range of newer chemical and catalytic methods. [Pg.956]

The wider utility of palladium metal catalysts and hydride cleavage of allylic systems has more or less replaced interest in using platinum-based catalysts such as Adams catalyst. Where this has been used for conjugation-stabilized allylic centers good yields have been achieved." The use of platinum for de-benzylation at low H2 pressure is effective." ... [Pg.963]

Selenides (selenoethers)and tellurides can be prepared via RSe and RTe species, and selenium and borohydride exchange resin followed by the halide give the selenoether. The La/l2-catalyzed reaction of diphenyl diselenide with primary alkyl iodides gave arylalkyl selenides, and Inl has been used with benzyl halides. Diaryl selenides (Ar—Se—AF) have been prepared by couphng aryl iodides with tin reagents (ArSeSnR3) with a palladium(O) catalyst. ... [Pg.552]

Very recently another reaction, which involves a palladium-catalyzed benzyl halide carbonylation step, has been commercialized by Clariant AG. Here, the carbonylation of 1,2-xylyl dichloride in the presence of a palladium-phosphine catalyst yields isochromanone (eq. (10)) [54]. [Pg.149]

Baeyer-Villiger m-Chloroperbenzoic acid. benzylic Palladium acetate. catalyst Platinum. [Pg.515]

Reduction of aromatic nitro groups using triethylammonium formate, catalyzed by pal-ladium-on-carbon or a soluble triaryphosphine-palladium acetate catalyst is compatible with ester or amide functions, leading to a-amino esters . The nitro group of the pyra-none 2 is selectively reduced, without hydrogenolysis of the benzyl ether linkage in the presence of finely divided Ni ° ... [Pg.300]

Based on the palladium-catalyzed carbonylation of benzylic halides Sheldon and co-workers investigated the functionalization of 5-hydroxymethylfurfural (HMF) to 5-formylfuran-2-acetic acid (FFA) in aqueous medium in the presence of a water-soluble palladium/TPPTS catalyst (Scheme 3) [5], Here, the hydroxy group displays similar reactivity under acidic conditions compared with benzylic halides. [Pg.505]

Oxidations of methylaromatic compounds, without phenolic group, in the presence of palladium based catalysts are well documented (ref. 9). Toluene (ref. 9), o-, m-, p-xylene (refs. 9c-e), mesitylene (ref. 9c), hexamethylbenzene (ref. 9c), o-methylanisole (ref. 9e) and p-methylanisole (ref. 9d) are among the main substrates which have been studied. The solvent of choice for the reaction is acetic acid and the main product is the corresponding benzylic acetate. Aldehyde... [Pg.381]

Carbonylation of benzyl chloride in the presence of a palladium based catalyst. [Pg.27]

Kinetic resolution of some secondary allylic and benzylic alcohols has been shown to occur efficiently in the presence of the chiral ligand (—)-sparteine. For example, partial oxidation of the racemic alcohol 43 with a palladium(II) catalyst under an atmosphere of oxygen in the presence of (—)-sparteine occurs to give a mixture of the ketone 44 and recovered alcohol (5)-43 (6.39). Selective oxidation of the (i )-alcohol occurs with the chiral catalyst system. [Pg.389]


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Benzyl halides palladium catalysts

Benzylic halides palladium catalysts

Palladium benzylation

Palladium catalysts catalyst

Palladium,benzyl catalyst acylation

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