Aryl alcohol

With Alcohols, Ethers, and Esters. Carbon monoxide reacts with alcohols, ethers, and esters to give carboxyHc acids. The reaction yielding carboxyHc acids is general for alkyl (53) and aryl alcohols (54). It is cataly2ed by rhodium or cobalt in the presence of iodide and provides the basis for a commercial process to acetic acid. 

The course of reduction of unsaturated and aromatic ketones is more complicated. Diaryl ketones, alkylaryl ketones and some aryl alcohols are smoothly reduced to the corresponding hydrocarbons. The recommended way of performing these reductions is to add an equimolar mixture of aluminum chloride and the ketone in ether to an equimolar mixture of aluminum chloride and LiAlH4 in ether. 

The method is not restricted to secondary aryl alcohols and very good results were also obtained for secondary diols [39], a- and S-hydroxyalkylphosphonates [40], 2-hydroxyalkyl sulfones [41], allylic alcohols [42], S-halo alcohols [43], aromatic chlorohydrins [44], functionalized y-hydroxy amides [45], 1,2-diarylethanols [46], and primary amines [47]. Recently, the synthetic potential of this method was expanded by application of an air-stable and recyclable racemization catalyst that is applicable to alcohol DKR at room temperature [48]. The catalyst type is not limited to organometallic ruthenium compounds. Recent report indicates that the in situ racemization of amines with thiyl radicals can also be combined with enzymatic acylation of amines [49]. It is clear that, in the future, other types of catalytic racemization processes will be used together with enzymatic processes. 

Guillen F, AT Martinez, MJ Martinez (1992) Substrate specificity and properties of the aryl-alcohol oxidase from the ligninolytic fungus Pleurotus eryngii. Eur J Biochem 209 603-611. 

Muheim A, R Waldner, MSA Leisola, A Fiechter (1990) An extracellular aryl-alcohol oxidase from the vihite-rot ivmgm Bjerkandera adusta. Enzyme Microbiol Technol 12 204-209. 

Scheme 12.53 Example of kinetic resolution of alkyl-aryl alcohols...

Pal, B., Sen, P.K. and Sen Gupta, K.K. (2001) Reactivity of alkanols and aryl alcohols towards tetrachloroaurate(lll) in sodium acetate-acetic acid buffer medium. Journal of Physical Organic Chemistry, 14, 284. 

Even if hundreds of chiral catalysts have been developed to promote the enantioselective addition of alkylzinc reagents to aldehydes with enantioselectivities over 90% ee, the addition of organozinc reagents to aldehydes is not a solved problem. For example, only very few studies on the addition of vinyl groups or acetylides and even arylzinc reagents to aldehydes have been published, in spite of the fact that the products of these reactions, chiral allylic, propargylic and aryl alcohols, are valuable chiral building blocks. 

Aryl alcohol oxidase from the ligninolytic fungus Pleurotus eryngii had a strong preference for benzylic and allylic alcohols, showing activity on phenyl-substituted benzyl, cinnamyl, naphthyl and 2,4-hexadien-l-ol [103,104]. Another aryl alcohol oxidase, vanillyl alcohol oxidase (VAO) from the ascomycete Penicillium simplicissimum catalyzed the oxidation of vanillyl alcohol and the demethylation of 4-(methoxymethyl)phenol to vanillin and 4-hydro-xybenzaldehyde. In addition, VAO also catalyzed deamination of vanillyl amine to vanillin, and hydroxylation and dehydrogenation of 4-alkylphenols. For the oxidation of 4-alkylphenol, the ratio between the alcohol and alkene product depended on the length and bulkiness of the alkyl side-chain [105,106]. 4-Ethylphenol and 4-propylphenol, were mainly converted to (R)-l-(4 -hydroxyphenyl) alcohols, whereas medium-chain 4-alkylphenols such as 4-butylphenol were converted to l-(4 -hydroxyphenyl)alkenes. 

Varela, E., Guillen, F., Martinez, A.T. and Martinez, M.J. (2001) Expression of Pleurotus eryngii aryl-alcohol oxidase in Aspergillus nidulans purification and characterization of the recombinant enzyme. Biochimica et Biophysica Acta, Protein Structure and Molecular, Enzymology, 1546 (1), 107-113. 

Numerous enantioselective transfer hydrogenation processes have now been developed and operated at commercial scale to give consistent, high-quality products, economically. These include variously substituted aryl alcohols, styrene oxides and alicyclic and aliphatic amines. Those discussed in the public domain include (S)-3-trifluoromethylphenylethanol [48], (f )-3,5-bistrifluorophenylethanol [64], 3-nitrophenylethanol [92], (S)-4-fluorophenylethanol [lc], (f )-l-tetralol [lc], and (T)-l-methylnaphthylamine [lc]. 

N. Guchhait, T. Ebata, and N. Mikami, Discrimination of rotamers of aryl alcohol homologues by infrared ultraviolet double resonance spectroscopy in a supersonic jet. J. Am. Chem. Soc. 121, 5705 5711 (1999). 

Acetylsalicylate deacetylase Aspirin esterase, aspirin hydrolase Acetyl esters of aryl alcohols, negatively charged esters... 

Ferraboschi, P., Grisenti, P., Manzocchi, A. and Santaniello, E., Baker s yeast-mediated preparation of optically active aryl alcohols and diols for the s3mthesis of chiral hydroxy acids. 

These findings led to the proposition that the veratryl alcohol is degraded via the quinone intermediates (Figure 5) to CO2 through a series of transformations involving lignin peroxidase, perhydroxy radicals and the NADP-dependent aryl alcohol oxidoreductase. Veratraldehyde, the major product of lignin peroxidase catalyzed veratryl alcohol oxidation, is rapidly reduced back to veratryl alcohol it is the further metabolism of the side products of the oxidative process, viz. the quinones and lactones, that drives the overall transformation towards completion (34). 

Z)-Trisubstituted aRylic alcohols. The conditions used by Bestmann et al. (7, 329) for preparation of (Z)-disubstitutcd alkcncs via the Wittig reaction also can provide a stereoselective route to (Z)-trisubstiluted allylic alcohols. An example is the reaction of ethylidenetriphenylphosphorane with the THP ether of hydroxy-acetone (equation 1). The stereoselectivity is decreased with other protecting... 

Ullrich R, Niiske J, Scheibner K, Spantzel J, Hoffichter M (2004) Novel Haloperoxidase from the Agaric Basidiomycete Agrocybe aegerita Oxidizes Aryl Alcohols and Aldehydes. Appl Environ Microbiol 70 4575... 

Ogawa, S. Furukawa, N. Regiospecific ortho lithiation of o-halophenyl p-tolyl sulfoxides and synthesis of met -substituted optically active aryl alcohols./. Org. Chem. 1991, 56, 5723-5726. 

Aryl alcohol dehydrogenase AAD14 Yn 331c 41,856 6.51 Unknown Soluble, cytoplasm... 

Putative aryl alcohol dehydrogenase AAD15 Yoll65c 15,618 5.78 Unknown Unknown... 

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