Ketones, from phenols

Hydroxy Ketones from Phenolic Esters (Fries). 544... 

The Fries rearrangement used for the preparation of aryl ketones from phenolic esters is now one of the most significant reactions in the synthetic chemistry of aromatic compounds, both in the classical version (equation 99) and in the newest modifications (see Section IV.D.3). 

Ozone (s. a. under (CH COO)2Co) Ketones from phenol ring viaa,/ -ethylene-y-hydroperoxy-7-lactones with retroaldol reaction... 

Analysis Another lactone FGl reveals the true TM (A). Our normal discormection a of an a,p-unsaturated carbonyl compound gives us the 1,5-dicarbonyl compound (B) and the ketone (C) clearly derived from phenol. Alternatively we could disconnect bond b to the keto-ester (D) with the further discormection shown ... 

For the oxidation of allylic alcohols to alkene ketones, see Section 168 (Ketones from Alcohols and Phenols)... 

VolatUe Compounds fkom Heated Beef Fat. Um et aL (30) studied the volatile lipids in fraction FI from extractions at 207 bar/Sfr C and 345 bar/S0°C using the qualitative GLC/MS method of Suzuki and Bailey (25). They identified 71 compounds in fraction FI of the extracts and quantified 66 compounds including 17 hydrocarbons, 4 terpenoids, 15 aldehydes, 3 ketones, 4 phenols, 10 carboj lic acid 6 esters and 7 lactones. 

Raspberry ketone is prepared by alkali-catalyzed condensation of the alkali salt of 4-hydroxybenzaldehyde and acetone, followed by selective hydrogenation of the double bond in the resulting 4-hydroxybenzalacetone. Other syntheses start from phenol which is converted into 4-(4-hydroxyphenyl)-2-butanone with methyl vinyl ketone (e.g., in the presence of phosphoric acid) [179] or with 4-hydroxy-2-butanone in the presence of concentrated sulfuric acid [180]. 

Both 6FDA-PFMB and BPDA-PFMB could be solution-cast into 1-100-pm-thick tough films. 6FDA-PFMB was cast from ketone or ether solutions, and the less-soluble BPDA-PFMB was cast from phenolic solutions. The films were... 

Sulphuric acid (concentrated). Widely used in desiccators. Suitable for drying bromine, saturated hydrocarbons, alkyl and aryl halides. Also suitable for drying the following gases hydrogen, nitrogen, carbon dioxide, carbon monoxide, chlorine, methane and paraffins. Unsuitable for alcohols, bases, ketones or phenols. Also available with an indicator (a cobalt salt, blue when dry and pink when wet) under the name Sicacide (from Merck) for desiccators. 

Since the Friedel-Crafts reaction when applied to the phenol ethers yields the corresponding ketones far more easily than the same reaction applied to hydrocarbons (see Reaction XX. (6) (iv.)), it is noteworthy that the above reaction does not apply to the phenol ethers. To obtain aldehydes from them or from phenols, a modified method must be used (see pp. 104, 106). 

Aliphatic aldehydes and ketones and also aliphatic-aromatic ketones can be converted into the corresponding hydrocarbons alkyl-phenols can be obtained from phenolic-aldehydes and -ketones p-hydroxy-benzophenone yields p-benzylphenol benzoin and benzil yield dibenzyl anthraquinone yields anthracene dihydride. 

Triflates derived from phenols are carbonylated to form aromatic esters by using Pd-Ph3P. The carbonylation of triflates is 500 times faster if DPPP (XLIV) is used [219]. This reaction is a good preparative method of benzoates from phenols and naphthoates from naphthols [220]. Carbonylation of enol triflates derived from ketones and aldehydes affords a,/Cunsaturated esters. The enol triflate in 451 is more reactive than the aryl triflate and the carbonylation proceeds stepwise chemoselectively. At... 

The Grignard reagent 7 is made from the halide that comes eventually from phenol by chlorination and methylation.2 We shall discuss the synthesis of ketones like 6 in chapter 19. 

For instance, the telechelic diols were prepared from phenol, a fluorinated ketone and HF according to the following reaction ... 

Ketones arise from phenols by isomerization of unsaturated alcohols (37). Palladium is the most suited for this type of reaction because of its high isomerization activity coupled with a very low rate of reduction of the resulting ketones (6). Excellent yields of ketones often may be obtained rhodium will give at times quite substantial yields of cyclohexanones (50-65% methylcyclohexanones from cresols) (38), but in other reductions such as resorcinol, little ketone accumulates over either rhodium or platinum under conditions where it is a major product over palladium (29). 

The reaction will also occur if the vinyl or aryl halide is used in place of the triflate. However, t triflates have been more widely used as they are readily prepared from phenols or enolizable aldeh des or ketones. In these reactions, the presence of a source of halide (typically LiCl) is genera required. This maybe because the triflate is a counterion and is not bound to the metal as a ligand, transmetallation is to occur some other ligand must be added to give the necessary square coplan geometry. 

The anethole ring has two functional groups - an ether and a hydrocarbon side chain with a double bond. The ether is synthesized first - by a Williamson ether synthesis from phenol and CH3I. The hydrocarbon side chain results from a Friedel-Crafts acylation of the ether. Reduction of the ketone, bromination and dehydrohalogenation are used to introduce the double bond. 

---