Perfluoroalkyl synthesis

A one-pot synthesis of alkyl perfluoroalkyl ketones has been developed. Phosphoranes, generated in situ, are acylated with a perfluoroacyl anhydnde, and the resultmg phosphonium salts are hydrolyzed with alkali [4S (equation 48) Hydrolysis of a carbon-sulfur bond in 2-chloro-2,4,4-trifluoro-1,3-dithietane-S-trioxide, which can be obtained from 2,2,4,4-tetrachloro-l,3-dithietane by fluor-mation with antimony trifluoride followed by selective oxidations, opens the nng to produce 2-chloro-1,1,2-trifluorodimethyl sulfone [49] (equation 49)... 

Fluorinated alkenes and alkynes are highly activated toward nucleophilic attack and reaction with bifunctional nucleophiles is a fruitful area for the synthesis of heterocycles. A review on perfluoroalkyl(aryl)acety-lenes contains many examples (91RCR501). 

Peptide synthesis, 81 Perfluoroalkyl groups, 346 Personal protective equipment (PPE), 246... 

Synthesis of Perfluoroalkyl Iodides over Metal Catalysts in Gas Phase... 

Perfluoroalkyl)ethane thiols have been used as precursors to fluorinated surfactants and products for hydro- and oligophobic finishing of substrates such as textiles and leather (1). The synthesis of 2-(perfluoroalkyl)ethane thiol and a byproduct bis-(-2-perfluoroalkylethane)-disulfide (5-10%) has been practiced via the reaction of 2-(perfluoroalkyl)ethane iodide with thiourea to form an isothiuronium salt which is cleaved with alkali or high molecular weight amine as shown in Equation 1 for 2-(perfluorohexyl)ethane iodide (1). 

The subjects of this chapter are the exploration of the scope and hmitations of the new Pd-Sn catalyzed hydrogenolysis route for the synthesis of thiols via 2-(perfluoroalkyl)ethane thiocyanate, the characterization of the surprisingly active and robust Pd-Sn catalysts, and the attempted correlation of the characterization of the catalysts with observed onset of hydrogenolysis reactivity and snrprisingly long lifetime in the presence of known catalyst poisons. ... 

The procedure illustrates a fairly general method for the preparation of -substituted perfiuoroolefins. The method has been applied to the synthesis of 2-cyclohexyl- (70%), 2-benzyl- (61%), and 2-(/>-fluorophenyl)perfluoropropenes (67%), and it is probably applicable to any a-trifluoromethyl ketone. Olefins containing a perfluoroalkyl group other than trifluoromethyl can be prepared by the same procedure by the substitution of lithium chlorodifluoroacetate for sodium chlorodifluoroacetate.7 Other routes to / -substituted perfiuoroolefins are not general or convenient. Routes to perfiuoroolefins generally yield the a-substi-tuted olefin rather than the /3-substituted olefin. 

WITTIG OLEFINATION OF PERFLUOROALKYL CARBOXYLIC ESTERS SYNTHESIS OF 1,1,1-TRIFLUORO-2-ETHOXY-5-PHENYLPENT-2-ENE AND 1-PERFLUOROALKYL EPOXY ETHERS 1,1,1-TRIFLUORO-2-ETHOXY-2.3-EPOXY-5-PHENYLPENTANE (Oxirane, 2-ethoxy-3-(2-phenylethyl)-2-(trifluoromethyl)-, cis-(+)-)... 

The C02-philic perfluoroalkyl-substituted (R,S)-3-H F -BINAPHOS ligand [34] was successfully applied to enantioselective hydrogenation in the inverted SCCO2/H2O system. The complex [Rh(cod)2]BARF was chosen as metal source and the active catalyst was formed in situ. Using the same procedure as above, similar activities and more than 98% ee were obtained consistently over five subsequent cycles in the hydrogenation of methyl 2-acetamido acrylate. The results demonstrate the potential of the inverted SCCO2/H2O system for asymmetric synthesis of chiral biologically active products. 

Perfluoroalkyl)dibenzothiophenium salts and their selenium and tellurium analogs are novel perfluoroalkylating agents. The synthesis and reactivity of these compounds are covered by T. Umemoto (Ibaraki, Japan). Finally, the first detailed survey of the chemistry of 1,3-oxazinium and 3-azapyrylium salts for over twenty years is provided by S. Lukyanov (Rostov-on-Don, Russia). 

The original preparation of 6-C-perfluoroalkyl-D-fructose has been reported. The first step of this synthesis is the perfluoroalkylation of acrolein acetal. The key step of the synthesis is an aldol condensation between D-3-fluoroalkylglyceraldehyde and dihydroxyacetone phosphate, with RAMA as biocatalyst (RAMA is an aldolase found in rabbit muscles) (Figure 6.43). ... 

---