1:1: 1-Trifluoroacetone

Fluoroolefins may he prepared by the reaction of Wittig reagents and other pho sphorus-containtng y tides with fluorinated carbonyl compounds. (A discussion of the fluorinated Wittig reagents or other fluonnated phosphorus reagents with nonfluorinated carbonyl compounds is on page 581.) Tnphenylphosphoranes, derived from alkyltriphenyl phosphonium salts, react with 1,1,1-trifluoroacetone [3/] or other trifluoromethyl ketones [32, iJ] (equation 26) (Table 10). 

Other ketones besides acetone can be used for in situ generation of dioxi-ranes by reaction with peroxysulfate or another suitable peroxide. More electrophilic ketones give more reactive dioxiranes. 3-Methyl-3-trifluoromethyldioxirane is a more reactive analog of DMDO.99 This reagent, which is generated in situ from 1,1,1-trifluoroacetone, can oxidize less reactive compounds such as methyl cinnamate. 

Organoaluminum reagents, 202 1,1,1-Trifluoroacetone, 323 Trityllithium, 338 Zinc chloride, 349 Stereoselective aldol reactions With boron enolates Boron trichloride, 43 Chlorodimethoxyborane, 73 9-(Phenylseleno)-9-borabicyclo-[3.3.1]nonane, 245 With silyl enol ethers... 

Triethynylantimony, 2118 Triethynylarsine, 2089 1,3,5-Triethynylbenzene, 3437 Triethynylphosphine, 2117 Triferrocenylcyclopropenium perchlorate, 3879 Triflic acid , see Trifluoromethanesulfonic acid, 0374 Trifluoroacetamide, 0700 Trifluoroacetic acid, 0661 Trifluoroacetic anhydride, 1362 f 1,1,1-Trifluoroacetone, 1097... 

Ketones can be converted to dioxiranes by Oxone (2KHSO5 KHSO4 K2SO4) under shghtly alkaline conditions (pH 7-8) (400). The dioxirane of 1,1,1-trifluoroacetone is a powerful yet selective oxidant under mild conditions, typically at temperatures below 313 K (10). Exemplary reactions are stereospecific olefin epoxidation and hydroxylation of tertiary C-H groups, or ketonization of CH2 groups. With chiral ketones, even enantioselective reactions are possible (401). Although the reactions are often performed in excess ketone, it is actually possible to use the ketone in a catalytic fashion, for example, for 1,1,1-trifluoroacetone (Scheme 5). 

Several groups have attempted the anchoring of ketone catalysts for use in combination with Oxone (404-407). One of the incentives for anchoring the catalyst is that the most suitable ketone, 1,1,1-trifluoroacetone, is highly volatile. A solid-bound, nonvolatile ketone therefore offers obvious handling and cost advantages. In one approach, 4-(trifluoroacetyl)benzoic acid was anchored to a graft copolymer of polystyrene and polyoxyethylene (17a) (406) alternatively, aliphatic ketones were covalently bound to silica (17b) (405, 407). 

Absolute rate constants for quenching of 19a have been reported for other ketones besides acetone, although product studies were not carried out42. These data are included in Table 3. The rate constant for quenching by pinacolone [54 kq = (4.0 0.2) x 108 M s-1] is similar to that by acetone under similar conditions, as would be expected for ene-addition by the mechanism of equation 46. The factor of ca 20 reduction in the rate constant for quenching by 1,1,1-trifluoroacetone [55 kq = (1.6 0.1) x 107 M 1 s 1]... 

How do 1,1,1-trifluoroacetone and formaldehyde react with piperidine, and what is the structure of product N ... 

The probable mechanism of the reaction is first addition of piperidine to formaldehyde to form /V-hydroxymethylpiperidine. This reacts with acidic hydrogens of the methyl group of 1,1,1-trifluoroacetone, which is hydrated because the trifluoromethyl group next to carbonyl stabilizes the hydrated form of the carbonyl compound. The resulting dihydrate is further stabilized by hydrogen bonds to the piperidine nitrogen 103. ... 

Recently, Mello et al. have disclosed a simple and robust protocol for the generation of methyl(trifluoromethyl)-dioxirane from an aqueous solution of 1,1,1-trifluoroacetone hydrate, sodium bicarbonate, and peroxomonosulfate on a preparative scale (typically <2 g the authors suggest multiple iterations for larger scales). The methyl(trifluoro-methyl)dioxirane is removed from the reaction mixture by the evolved gases (O2, CO2) and has been applied to the oxidation of substrates in a second reaction zone (e.g., the epoxidation of cyclohexenone Scheme 33) <2007S47>. 

Sieger and Calvert reported the photolysis products of 1,1,1-trifluoroacetone at A 3130 A to be carbon monoxide, methane, ethane, 1,1,1-trifluoroethane, and hexafluoroethane. A low quantum yield for decomposition near room temperature may be explained in terms of the excited trifluoroacetone having an appreciable lifetime and therefore suffering possible collisional deactivation before decomposition can occur. Two possible primary stepts of Type 1 have been proposed... 

The thermal decomposition of 1,1,1,-trifluoroacetone has been studied by Fekete - , and that of fluoroacetone hemiacetal esters by Newallis et Lewis and Newman have reported on the rearrangements of fluoroesters in the gas phase. Thermal reactions of nitrogen-containing fluoro-compounds have included trifluoromethyl cyanide , hexafluoroazomethane , tetrafluorohydra-zine , fluorodiazirines , perfluoropyridazines , fluorochlorodinitrometh-ane and poly(difluoroamino)fluoromethanes - . ... 

Methyl(trifluoromethyl)dioxiiane (TFDO), prepared from 1,1,1-trifluoroacetone and KHSOg, is more reactive than DMDO by a factor of 600. In addition to facile epoxidation of alkenes, TFDO can be used to regioselectively oxidize tertiary over secondary C-H bonds via an oxenoid (butterfly) mechanism. ... 

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