Perfluoroalkyl aldehyde

Perfluoroalkyl iodides reacted with trialkylsilyl chloride in DMF in the presence of zinc followed by hydrolysis with acid to give perfluoroaldehydes in good yields [55]. Recently, Hu reported a new preparation of perfluoroalkyl aldehydes via reaction of perfluoroalkyl halides and DMF, initiated by redox... 

The fluoroform reaction has also been observed with higher perfluoroalkyl aldehydes and perfluoroalkyl ketones, which react with formation of l//-perfluoroalkanes and carboxylic acids. 

Organozinc reagents. Zn-Cu couple often shows higher reactivity than zinc dust towards alkyl halides. Thus perfluoroalkylzinc iodides are rapidly formed in the presence of AIBN, and quenching such reagents in situ by DMF gives perfluoroalkyl aldehydes. (Note that Zn-Ag on graphite is well suited for the preparation of aryl-zinc species). ... 

The original method for the preparation of 2-perfluoroalkyl benzothiazoles by reaction of a-perfluoroalkyl aldehydes with 2-aminobenzenethiole includes dehydrofluoii-nation, Michael addition-cyclization followed by elimination of acetaldehyde [102]. 

We observed similar results with two other perfluoroalkyl aldehydes, 2,2,3,3,3-pentafluoropropionaldehyde, and 2,2,3,3,4,4,4-heptafluorobutyraldehyde. 

It has been reported that 1,1,1-trifluoroacetone trimeiizes in the presence of amines (Scheme 8) (18). Although we observed some reaction in die case of perfluoroalkyl aldehydes, ethyl acrylate and methyl vinyl ketone failed to react with 1,1,1-trifluoroacetone. Acrolein and acrylonitrile provided -10% yield of the product along with the trimer. 

The reaction of perfluoroalkyl iodides with calcium amalgam at -20 to 40 °C has been used to prepare perfluoroalkyl carbinols in 30-70% yields [/, 2] Aromatic aldehydes (equation 1) and ketones (equation 2) undergo this reaction, aliphatic aldehydes give high boiling mixtures The results are interpreted in terms of the intermediate formation of an organocalcium species... 

In related work, palladium, nickel, or methyl viologen (MV ) were used to catalyze the conversion of perfluoroalkyl iodides to a-perfluoroalkyl carbinols in the presence of zinc [43, 44] (equations 32 and 33) Only aldehydes react under these conditions... 

Barbier conditions have been used to carry out a silicon-induced addition of perfluoroalkyl iodides to DMF to give stable hemiaminal intermediates, which give the perfluonnated aldehydes upon heating with sulfuric acid [47 (equation 38)... 

Perfluoroalkyl- and perfluoroaryltitanium compounds were prepared m situ via reaction of the corresponding Gngnard reagents with chlorotris(diethyl-amido)titanium [28S] Reaction of the titanium compounds with aldehydes resulted in fluoroalkylative amination [288] (equation 192)... 

This method can also be utilized as a general method for the preparation of olefins with terminal difluoromethylene groups from aldehydes.8 Also, by the substitution of tributylphosphine for triphenylphosphine in this procedure, ketones other than those containing an a-perfluoroalkyl group can be converted to terminal difluoromethylene compounds.9... 

These types of compounds can also be formed via a Wittig reaction [19]. Triphenylphosphine can be quatemized with a suitable alkyl iodide, and the resultant perfluoroalkylated phosphonium salt will react with aldehydes to give fluorinated alkenes which are easily hydrogenated (Scheme 3.4). This methodology has recently been expanded to the formation of perfluoroalkylated pyridines [20],... 

A similar reaction has been conducted under fluorous biphasic conditions, using a perfluoroalkylated bipyridine as ligand to ensure that the copper species resides in the fluorous phase [22], The oxidation of a range of primary alcohols to the corresponding aldehydes was found to be possible, an example of which is shown in Scheme 9.11. The catalyst could be successfully recycled by phase separation, with analytically pure products being isolated even after... 

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). 

Gly-OEt was also added to ethyl 3-perfluoroalkylpropynoates which were transformed in several steps into 5-perfluoroalkyl-substituted l-methyl-2-ethoxycarbonylpyrrolidin-3-ones (90X6705). 3-Propyl- and 4-propylpro-lines and 4- -pentylproline were synthesized from diethyl acetamidomalo-nate and an unsaturated aldehyde (67JA2459 72JMC1255). Ethyl benzyli-denecyanoacetate reacts with hippuric acid to give the pyrrole 8 (87H2323). 

Perfluoroalkyl lithium reagents undergo reactions typical of their hydrocarbon analogs. For example, perfluoroalkyl lithium reagents generated in situ from perfluoroalkyl iodides and alkyl lithiums reacted readily with aldehydes and ketones to yield the corresponding secondary and tertiary carbinols, and with esters to give either ketones or tertiary carbinols [12]. No 1,4-addition product is observed when a,/ -unsaturated ketones and esters are employed. 

Similarly,palladium, nickel complex [49] or methyl viologen (MV2+) [50] have also been used to catalyze the reaction of perfluoroalkyl iodides with aldehydes in the presence of zinc to give the corresponding a-perfluoroalkyl carbinols (Scheme 17). 

The benzene derivatives containing the fluorinated sulfone have been prepared either by nucleophilic substitution of the 4-fluorophenyl derivative (e.g. 1) or by starting with the appropriately substituted sodium thiophenoxide and reacting with perfluoroalkyl iodide follow by oxidation with either MCPBA or chromium oxide (12. li.) The biphenyl derivatives have been prepared by palladium catalyzed cross coupling chemistry of the 4-bromophenyl derivative (e.g. 2) with substituted phenyl boronic acid (yields 37-84%) (JLH, .). Compound 16 has been prepared by palladium catalyzed cross coupling of (4-bromophenyl)perfluorohexyl sulfone with vinyl anisole in 37 % yield (JJL). The vinyl sulfones, 7 and 9, have been prepared by condensation of CH3S02Rf (JJL) with the appropriate aldehyde (yields 70,and 73%) following a literature procedure (1 ). Yields were not optimized. 

The diphenylprolinol silyl ether 45a catalyst was developed by the Hayashfs group for the addition of a-unbranched aldehydes to aryl and alkyl substituted nitroolefins [35]. This catalyst, as well as the perfluoroalkyl derivative 45b [36],... 

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