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Benzyl alcohol bond unsaturation

The chemistry of indium metal is the subject of current investigation, especially since the reactions induced by it can be performed in aqueous solution.15 The selective reductions of ethyl 4-nitrobenzoate (entry 1), 2-nitrobenzyl alcohol (entry 2), l-bromo-4-nitrobenzene (entry 3), 4-nitrocinnamyl alcohol (entry 4), 4-nitrobenzonitrile (entry 5), 4-nitrobenzamide (entry 6), 4-nitroanisole (entry 7), and 2-nitrofluorenone (entry 8) with indium metal in the presence of ammonium chloride using aqueous ethanol were performed and the corresponding amines were produced in good yield. These results indicate a useful selectivity in the reduction procedure. For example, ester, nitrile, bromo, amide, benzylic ketone, benzylic alcohol, aromatic ether, and unsaturated bonds remained unaffected during this transformation. Many of the previous methods produce a mixture of compounds. Other metals like zinc, tin, and iron usually require acid-catalysts for the activation process, with resultant problems of waste disposal. [Pg.100]

Oxidations with peimanganates are suitable for the preparation of carboxylic acids from saturated and benzylic alcohols. Unsaturated alcohols may suffer cleavage of double bonds. Conventional oxidations are carried out in aqueous media, usually in the presence of alkali hydroxides. Thus... [Pg.128]

Reductive cleavage is facilitated when the anions are stabiUzed by resonance or by an electronegative atom. As expected, therefore, bonds between heteroatoms or between a heteroatom and an unsaturated system which can stabilize a negative charge by resonance, are particularly easily cleaved. Thus allyl and benzyl ethers and esters (and sometimes even allyl or benzyl alcohols) are readily cleaved by metal-amine systems (or by catalytic hydrogenation). This type of reaction has... [Pg.432]

Unsaturated alcohols which have the double bond farther removed from the hydroxyl group are reacted in good yields. The reaction of tetrahydro-benzyl alcohol was investigated in detail [174]. [Pg.53]

Finally, allene derivatives were also convenient unsaturated substrates allowing carbon-carbon bond formation from benzylic alcohol via hydrogen transfer processes. With these substrates, the best catalytic systems were based on RuHCl (CO)(PPh3)3 in the presence of an equimolar amount of phosphine ligand such as bis(diisopropylphosphino)ferrocene (dippf) [63], bis(dicyclohexyphosphino) ferrocene or PCyPh2 [64], Some examples of selective formation of homoallylic alcohols using this reaction are reported in Scheme 59. [Pg.230]

The hydration of C-C multiple bonds is a reaction with prevalent industrial interest due to the usefulness of the products as chemical intermediates. The wool-Pd complex is an economical and highly active catalyst for hydration of olefins. It is very stable and can be reused several times without any remarkable change in the catalytic activity [73, 74]. In particular, to convert alkenes to the corresponding alcohols in excellent enantioselectivity, a new biopolymer-metal complex constituted of wool-supported palladium-iron or palladium-cobalt was prepared and used, such as allylamine to amino-2-propanoI, acrylonitrile to lactonitrile and unsaturated acids to a-hydroxycarboxylic acids [75-77]. The same catalytic system was also used for hydration of substituted styrenes to produce chiral benzyl alcohols. The simple and cleaner procedure, mild reaction conditions, high stability and recovery rate of catalyst made these catalytic systems an attractive and useful alternative to the existing methods (Scheme 37). [Pg.254]

The reaction of diethylamine or alcohol with 2,3-allenamide 551 affords /3-diethyl-amino-a,/3-unsaturated enamide 555, indicating the migration of the C=C bond under basic conditions. The corresponding reaction of 551 with benzyl thiol proceeded to afford /j-thiobenzy 1-/1,y-unsatu rated enamide 556 the /i,y-C=C bond can migrate to the a,/3-position on the treatment with DBU in THF to afford 557 [257]. In reactions of 4,4-dichloro-2,3-butenamide 558 with amines, thiolates and alcohols, ce,/j-unsaturated enamides 560-564 are always formed on treatment with a base [258, 259]. [Pg.682]

Chromium(II) sulfate is a versatile reagent for the mild reduction of a variety of bonds. Thus aqueous dimethylformamide solutions of this reagent at room temperature couple benzylic halides, reduce aliphatic monohalides to alkanes, convert vicinal dihalides to olefins, convert geminal halides to carben-oids, reduce acetylenes to /raw5-olefins, and reduce a,j3-unsatu-rated esters, acids, and nitriles to the corresponding saturated derivatives. These conditions also reduce aldehydes to alcohols. The reduction of diethyl fumarate described in this preparation illustrates the mildness of the reaction conditions for the reduction of acetylenes and o ,j8-unsaturated esters, acids, and nitriles. [Pg.52]

Addition of 0- to double bonds and to aromatic systems was found to be quite slow. Simic et al. (1973) found that O- reacts with unsaturated aliphatic alcohols, especially by H-atom abstraction. As compared to O, HO reacts more rapidly (by two to three times) with the same compounds. In the case of 1,4-benzoquinone, the reaction with O consists of the hydrogen double abstraction and leads to the 2,3-dehydrobenzoquinone anion-radical (Davico et al. 1999, references therein). Christensen et al. (1973) found that 0- reacts with toluene in aqueous solution to form benzyl radical through an H-atom transfer process from the methyl group. Generally, the O anion-radical is a very strong H-atom abstractor, which can withdraw a proton even from organic dianions (Vieira et al. 1997). [Pg.58]

The oxidation of benzylic type alcohols and alkenols with the double bond more than three carbon atoms distant from the hydroxyl group leads to unsaturated carboxylic... [Pg.107]

Aminothiazole, with acetaldehyde, 42 to 2-mercaptothiazoie, 370 4-Aminothiazole-2,5-diphenyl, to 2,5 di-phenyl-A-2-thiazoline-4-one, 421 Ammothiazoie-A -oxide, 118 2-Aminothiazoles. 12 acidity of, 90 and acrylophenone, 42 acylations of, with acetic acid. 53 with acetic anhydride, 52 with acyl halides, 48 with chloracetyl chloride, 49 with-y-chlorobutyrylchloride, 50 with 0-chloropropionylchloride, 50 with esters, 53 with ethy acrylate, 54 with indoiyl derivatives, 48 with malonic esters, 55 with malonyl chloride, 49 with oxalyl chloride, 50 with sodium acetate, 52 with unsaturated acyl chloride, 49 additions to double bonds, 40 with aldehydes, 98 alkylations, with alcohols, 38 with benzyhydryl chloride, 34 with benzyl chloride, 80 with chloracetic acid, 33 with chloracetic esters, 33 with 2-chloropropionic acid, 32 with dialkylaminoalkyl halides, 33 with dimethylaminoethylchloride, 35 with ethylene oxide, 34, 38... [Pg.289]

Chromium(VI) oxide can be used as a catalytic oxidant for alcohols with r-butyl hydroperoxide as the cooxidant. This reagent appears to be selective for allylic and benzylic over saturated alcohols, though ( )/(Z)-isomerization has been observed during the preparation of a,3-unsaturated aldehydes. This reagent is also a good oxidant for allylic and ben lic C—bonds these may be competing pathways in more sophisticated substrates. ... [Pg.278]


See other pages where Benzyl alcohol bond unsaturation is mentioned: [Pg.233]    [Pg.33]    [Pg.67]    [Pg.551]    [Pg.956]    [Pg.228]    [Pg.906]    [Pg.231]    [Pg.558]    [Pg.398]    [Pg.17]    [Pg.385]    [Pg.371]    [Pg.742]    [Pg.153]    [Pg.27]    [Pg.19]    [Pg.188]    [Pg.2]    [Pg.354]    [Pg.526]    [Pg.8]    [Pg.158]    [Pg.501]    [Pg.501]    [Pg.251]    [Pg.10]    [Pg.496]    [Pg.104]    [Pg.125]    [Pg.372]    [Pg.235]    [Pg.380]    [Pg.855]    [Pg.496]   
See also in sourсe #XX -- [ Pg.71 ]




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Alcohol benzylation

Alcohols benzyl alcohol

Alcohols bonding

Alcohols unsaturated

Benzyl alcohol

Benzylation benzyl alcohol

Benzylic alcohols

Benzylic bonds

Unsaturated bond

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