Phenyl trifluoromethyl ketone

Trifluoromethyl phenyl ketone CF3-C(0)C6Hs 73.8 + 2 308.8 + 8.4 VLPP 1977COL/ZAB... 

The formation of equilibrium between carbonyl compounds and alcohols is general for this reaction, except for the reduction of trifluoromethyl phenyl ketone. The Meerwein-Ponndorf-Verley reduction has advantages of chemoselectivity, mild reaction conditions, operational simplicity, low cost, and scalability." " In addition, this reaction does not affect other double bonds or triple bonds as well as other enolizable carbonyl compounds (e.g., j8-keto ester, j8-diketone). The catalysts suitable for this reaction include aluminum alkoxide and some transition-metal alkoxides (e.g., zirconium," " iron, ... 

Monoalkyl ethers of (R,R) 1,2-bis[3,5-bis(trifluoromethyl)phenyl]ethanediol, 24, have been examined for the enantioselective protonation of silyl enol ethers and ketene disilyl acetals in the presence of SnCU (Scheme 12.21) [25]. The corresponding ketones and carboxylic acids have been isolated in quantitative yield. High enantioselectivities have been observed for the protonation of trimethylsilyl enol ethers derived from aromatic ketones and ketene bis(trimethylsilyl)acetals derived from 2-arylalkanoic acids. 

Interestingly, the newly developed Ar3BiCl2/DBU oxidants [Ar = p-nitrophenyl, p-(trifluoromethyl)phenyl] rapidly oxidize 2,2,2-trifluoro-l-phenylethanol [81], which is generally known to resist oxidation [85-87], to the corresponding trifluor-omethyl ketone within 5-50 min at room temperature (Scheme 21). The difference in the reaction rates among the bismuth(V) oxidants is in good agreement with the results obtained for the intermolecular competition experiments. 

Iodine-catalysed hydroperoxidation of cyclic and acyclic ketones with aqueous hydrogen peroxide in acetonitrile is an efficient and eco-friendly method for the synthesis of gem -dihydroperoxides and the reaction is conducted in a neutral medium with a readily available low-cost oxidant and catalyst.218 Aryl benzyl selenoxides, particularly benzyl 3,5-bis(trifluoromethyl)phenyl selenoxide, are excellent catalysts for the epoxidation of alkenes and Baeyer-Villiger oxidation of aldehydes and ketones with hydrogen peroxide.219 Efficient, eco-friendly, and selective oxidation of secondary alcohols is achieved with hydrogen peroxide using aqueous hydrogen bromide as a catalyst. Other peroxides such as i-butyl hydroperoxide (TBHP), sodium... 

IR spectra there is absorption in the region 1540-1620 cm-1, characteristic of the chelated cis-enol bands characteristic of a free carbonyl group are absent. The effect of substituents on the enolization of /3-di-ketones (in acetone) was studied by NMR spectroscopy. In the cu-acyl-2-acetoselenophene (20) and a> -acyl-3-acetoselenophene(21) series, the acyl groups COR increase the enolization in the following order of R methyl < a-furyl < a-thienyl < trifluoromethyl < phenyl < a-pyridyl. Thus, /S-diketones containing aroyl or heteroaroyl radicals together with selenienyl exist completely as the cis-enols.121... 

Trichloroacetamido)phenyl ketone.s 18 or their tribromo analogs are, in most cases, readily converted to the corresponding 4-substituted quinazolin-2(l//)-ones 19 by reaction with ammonia via loss of the trihalomethyl function. Under similar conditions, the 2-trifluoroac-etamide derivative reacts to yield 2-(trifluoromethyl)quinazoline. The mechani.sm of this... 

CAB 2, R = H, derived from monoacyloxytartaric acid and diborane is also an excellent catalyst (20 mol %) for the Mukaiyama condensation of simple enol silyl ethers of achiral ketones with various aldehydes. The reactivity of aldol-type reactions can, furthermore, be improved, without reducing the enantioselectivity, by use of 10-20 mol % of 2, R = 3,5-(CF3)2C6H3, prepared from 3,5-bis(trifluoromethyl)phenyl-boronic acid and a chiral tartaric acid derivative. The enantioselectivity could also be improved, without reducing the chemical yield, by using 20 mol % 2, R = o-PhOCgH4, prepared from o-phenoxyphenylboronic acid and chiral tartaric acid derivative. The CAB 2-catalyzed aldol process enables the formation of adducts in a highly diastereo- and enantioselective manner (up to 99 % ee) under mild reaction conditions [47a,c]. These reactions are catalytic, and the chiral source is recoverable and re-usable (Eq. 62). 

The thiourea derivative, l-[3,5-di(trifluoromethyl)phenyl]-2-thiourea (Tl) was purchased from Fluorochem Ltd (Derbyshire, UK). A 1000 ppm spectrosol solution of Au as an AuCV solution was obtained from BDH Chemicals Ltd. (Poole, England). All CO2 gas cylinders were fitted with dip tubes and bought from Irish Oxygen (Cork, Ireland). All extracted samples after SFE were collected in either methyl iso-butyl ketone (MIBK), DMSO (bodi purchased from BDH) or methanol (Merck, Germany) as indicated. 

The same substituent effect is present with trifluoromethyl aryl ketones. N/J, AfW-Tetramethyl-N"-(f-butyl)guanidine was an effective catalyst for reaction with trifluoromethyl ketones [123]. The reaction can be done enantioselectively using 3,3 -bw-(2,4,6,-tri-j-propyl-phenyl)BlNOL [ 124],... 

A mixture of benzaldehyde and trifluoromethyltrimethylsilane (as trifluoromethyl carbanion equivalent) in THF at 0° treated with tetra- -butylammonium fluoride, warmed to room temp., stirred for 1 h, and the siloxy deriv. hydrolyzed with 0.5 N HCl at room temp, for 1 h - trifluoromethyl(phenyl)carbinol. Y 85%. The method is generally applicable to aldehydes and ketones (inch enones), but hindered ketones required longer reaction times. F.e.s. G.K.S. Prakash et al., J. Am. Chem. Soc. 777, 393-5 (1989). 

A number of carbon-carbon bond formation reactions have been studied in detail by Chambers (22) and Filler 28). Some of these transformations show that significant steric hindrance is imposed by the 2,4,6-tris(trifluoromethyl)phenyl substituent. Steric effects became especially apparent in the failure of several attempts to prepare the acetophenone derivative RfC(0)CH3 and the related vinyl ketone RpC(0)CH=CH2 (28), The elusive 2,4,6-tris(trifluoromethyl)acetophenone is... 

L-Threonine-derived catalysts were demonstrated to be remarkably effective for the direct aldol reaction. Lu et al. investigated the potential of serine and threonine analogs in the direct asymmetric aldol reaction in aqueous medium [28]. While L-serine and L-threonine were found to be ineffective, sUylated threonine and serine derivatives were wonderful catalysts for the direct aldol reaction of cyclohexanone and aromatic aldehydes in the presence of water, affording the aldol adducts in excellent yields and with nearly perfect enantioselectivities. L-Serine-derived 9a was inferior to the corresponding threonine-based catalysts. The reaction could be extended to hydroxyacetone, and sy -diols were obtained with very good enantioselectivities (Scheme 3.6). Subsequently, Teo and coworkers also employed silylated serine catalysts for the same reaction [29]. Very recently, Cordova et al. [30] reported a co-catalyst system consisting of 8a and l,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, and applied such catalytic pairs to the direct aldol reaction between ketones and aromatic aldehydes both cyclic and acycUc ketones were found to be suitable substrates. 

Prakash and co-workers have prepared monofluoro-methyl 3,5-bis(trifluoromethyl)phenyl sulfone and have used it in the fluoroalkenylation of aldehydes and ketones.They employ KOH or CsF as base in DMSO at 20°C. On their side, Hu and co-workers have developed TBTSO2CH2F as a versatile fluoromethylidene synthon. Difluoromethyl 2-pyridyl sulfone has been used for the gem-difluoromethylenation of aldehydes and ketones and was found to be a more efficient difluoromethyfidene synthon than BTSO2CF2H, PTSO2CF2H and TBTS02CF2H. ... 

Synthetic applications of organosulfur reagents are expanding rapidly. Stable sulfuranes are included for the first time in BIS[2,-2,2-TRIPLUORO-l-PHENYL-l-(TRIFLUOROMETHYL)ETHOXY] diphenyl SULFURANE and DIETHYLAMINOSULFUR TRI-FLUORIDE. The latter is used to transform an alcohol to a fluoride in p-NITROBENZYL FLUORIDE. The direct homologation of a ketone to a nitrile by use of p-TOLYLSULFONYLMETHYL ISOCYANIDE is illustrated in 2-ADAMANTANECARBONITRILE. Reagents with... 

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