Aldehydes perfluoro

In a related process, a-halo ethers can be prepared by treatment of aldehydes and ketones with an alcohol and HX. The reaction is applicable to aliphatic aldehydes and ketones and to primary and secondary alcohols. The addition of HX to an aldehyde or ketone gives tx-halo alcohols, which are usually unstable, though exceptions are known, especially with perfluoro and perchloro species. °... 

Rate constants and Arrhenius parameters for the reaction of Et3Si radicals with various carbonyl compounds are available. Some data are collected in Table 5.2 [49]. The ease of addition of EtsSi radicals was found to decrease in the order 1,4-benzoquinone > cyclic diaryl ketones, benzaldehyde, benzil, perfluoro propionic anhydride > benzophenone alkyl aryl ketone, alkyl aldehyde > oxalate > benzoate, trifluoroacetate, anhydride > cyclic dialkyl ketone > acyclic dialkyl ketone > formate > acetate [49,50]. This order of reactivity was rationalized in terms of bond energy differences, stabilization of the radical formed, polar effects, and steric factors. Thus, a phenyl or acyl group adjacent to the carbonyl will stabilize the radical adduct whereas a perfluoroalkyl or acyloxy group next to the carbonyl moiety will enhance the contribution given by the canonical structure with a charge separation to the transition state (Equation 5.24). 

Pcrfluoroalkylation of polycyclic aryl aldehydes and ketones by trimethyl(perfluoroal-kyl)silanes in the presence of a metal fluoride gives perfluoroalkylated secondary and tertiary alcohols. For example, the formation of 15. ... 

Aromatic aldehydes give the corresponding alcohols on reaction with trimethyl(polylluoroal-kyl)silanes in lelrahydrofuran in the presence of tetramcthylammoniuni fluoridc. The reaction of perfluoro-2-propoxypropanoyl fluoride with trimethyl(perfluoroalkyl)silane leads to the perfluoroalkylated ketone product. ... 

In a limited number of cases, arylsilanes react with aldehydes as if they were aryl Grignard or aryllithium reagents. Both trimethyl(perchlorophenyl)silane and trimethyl(perfluoro-phenyl)silane react with benzaldehyde to give the corresponding 7.-(pcrhalophenyl)bcnzyl tri-methylsilyl ethers.163 Benzaldehyde reacts completely with trimethyl(perfluorophenyl)silane in diethyl ether in the presence of either a catalytic amount of the potassium cyanide/18-crown-6 complex in less than 5 hours at room temperature or potassium fluoride in dimethylform-umide.164 In the case of aryltrimcthylsilanes containing electron-withdrawing substituents in the ortho position, the reaction is observed only under the conditions of nucleophilic catalysis by potassium fluoride or cesium fluoride. 

Another highly fluorinated rare earth y9-diketonate, 21 (Ln = Pr, Eu, Ho dppm = di(perfluoro-2-propoxypropionyl)methanate), showed itself to be a delicate reagent, not only for accomplishing high chemoselectivity in Mukaijama aldol reactions with aldehydes and ketene silyl acetals (KSA) [123], for it was attributed with a mode of stereomodulating catalysis in the aldol reaction of alkoxy aldehydes with KSA (eqs. (12) and (13)). 

It has been shown that perfluorinated j3-diketonates are excellent catalysts for oxidation reactions in perfluorinated solvents [26]. The nickel catalyst Ni(39)2, prepared by reaction of the -diketone 39 [27] with NiCl2, catalyzes the oxidation of various (functionalized) aromatic and aliphatic aldehydes to the corresponding carboxylic acids in 76 to 87% yield in a solvent system of perfluoro-decaline and toluene at 64 °C under 02-atmosphere Eq. (16). 

Base-catalysed elimination reactions of oxaziridines produce aldehydes or ketones together with unstable N-unsubstituted imines. Recently this reaction has been used as a synthesis method for a range of more stable N-unsubstituted ketimines thus (355) with Me COK in THF at room temperature gives (356) (90 )2", Perfluoro compound (357) has been found to undergo facile cycloaddition reactions with F2C CFC1 and acetone to yield (358) and (359) respectively2-. ... 

Barlow, M.G. Coles, B. Haszeldine, R.N. Heterocyclic polyfluoro-compounds. Part 33. Photochemical oxetane formation from fluoro ketones and perfluoro aldehydes and 1,2-difluoroethylene. J. Chem. Soc., Perkin Trans. 1 1980, (10), 2258-2267. 

The hetero-Diels-Alder (HDA) reaction of 2,3-dimethylbuta-1,3-diene and cyclohexa-1,3-diene with ethyl glyoxylate catalysed by chiral Zn(II) complexes yields both the dihydropyran and the ene product, the former predominating. The enantiomeric excess, which can reach 87%, is dependent on the solvent as well as the catalyst <97JCS(P1)2345>. Use of (Rs,E)-3-[(15)-isoborneol-10-sulfinyl]-l-methoxybutadiene gives the 5,6-dihydropyran with good endo and facial diastereoselectivity <97TA2989>. Scandium(III) perfluoro-octanesulfonate is an efficient catalyst in the HDA reaction of aldehydes with non-activated dienes <97BCJ1421>. 

Chan et al. [19] used ligand fib in association with Ti(0-iPr)4 in the condensation of aromatic aldehydes with EtjAl in the biphasic hexane-perfluoro(methyldecalin) system at 53 °C [Eq. (2)]. Enantioselectivities in the range 76-88% ee and chemical yields of 77-82% were obtained during six consecutive runs when fresh titanium was added. When the reaction was extended to the electron-deficient 4-chlorobenzaldehyde, the yield was the same (59-88% for three runs) and the enantioselectivity a little lower (63-79% ee for three rrms) for the electron-rich 4-methoxybenzaldehyde, only 10% of product was obtained with an enantioselectivity of 38%. 

King. J.B. Tsunoda. M. Gabbai, F.P. Complexation of aldehydes and ketones by trimeric perfluoro-orf/to-pheny-lene mercury, a tridentate Lewis acid. Organometallics 2002. 21. 4201-4205. 

Radical Chain Addition Reactions of Aldehydes With Perfluoro Ketones and Chloro Perfluoro Ketones," J. Org. Chem., 347 (1967). 

HPICE lon- exdusion SO3- Ha Octane-sidfonic add Perfluoro-bulyric add Aliphatic carboxylic adds, borate, silicate, carbonate, alcohols, aldehydes... 

Kitazume and Ishikawa have published a number of communications on the regiospecific zinc mediated perfluoroalkylation of a variety of substrates [148-151]. A compilation of these results appeared in 1985 [152] (Scheme 71). Secondary alcohols are available in moderate yield by reaction of perfluoro-alkyl halides (RpX) with aldehydes as the result of a modified Barbier-type reaction [148-152]. However, reaction with ketones gave low yields of the expected tertiary alcohols, although the yields could be doubled by reaction in the presence of a bis[7i-cyclopentadienyl]titanium(II) catalyst, which was prepared in situ by reduction of the dichloride with zinc in the presence of ultrasound. 

At low temperatures perfluoro-w-propyllithium, prepared in the above manner, underwent displacement and addition reactions common to alkyl-lithium compounds. The experimental technique (7) involved addii methyllithium and the reactant dissolved in ether to heptafluoro- -propyl iodide in the same solvent. In this manner, certain aldehydes and ketones afforded the expected alcohols, and diethyldichlorosilane gave a mixture of the organosilanes n-C3F7(C2H5)2SiCl and ( -C3F7)2Si(C2H5)2. 

MBH Reaction of Perfluoro-aliphatic Aldehydes. Fluoral is known to polymerize in the presence of amines (Scheme 4) (16), However, we tested whether the polymerization is favored in the presence of activated olefms. 

Scheme 5. MBH reaction of perfluoro-aldehydes with ethyl acrylate...

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