Polyfluoroalkyl aldehydes

Tang XQ, Hu CM (1994) Direct synthesis of 3-(fluoroalkyl)pyrazoles from polyfluoroalkyl aldehydes. J Chem Soc Perkin Trans 1 2161—2163... 

Reagents involved in the oxidation of alcohols to aldehydes-ketones by oxygen under fluorous biphasic conditions are TEMPO, CuBr-SMe2, and 4,4 -bis[heptadecafluoro)-dodecyl]-2,2 -bipyridyl. The Mn(salen) complexes that mediate epoxidation of alkenes have been modified to bear polyfluoroalkyl substituents in the aromatic rings. Oxyfunc-tionalization of unactivated C—H sites is achieved with perfluorinated oj-2-butyl-3-propyloxaziridine. "... 

Polyfluoroalkylaldehydes. " Polyfluoroalkyl iodides are metalated by treatment of Al powder and catalytic amounts of PbBr2. The in situ reaction with DMF solvent gives the aldehydes. 

The use of trichloroacetaldehyde is also to be particularly noted. Although reactions between this aldehyde and various dialkyl hydrogenphosphonates have been report- 269,274,294,295 it is the dimethyl ester of (l-hydroxy-2,2,2-trichloroethyl)phosphonic acid which has received particular attention, and which has been studied widely from the structural point of view in the light of its commercial importance as the powerful insecticide dipterex (also known as trichlorphon and chlorophos). Polyfluoroalkyl esters of the related alkyl(l-hydroxy-2,2,2-trichloroethyl)phosphinic acids have been prepared by the unusual combination of chloral hydrate and the bis(polyfluoroalkyl) alkylphosphonite ester ... 

Francio and Leitner [83, 84] used a specially designed (U,S)-BINAPHOS ligand decorated with polyfluoroalkyl ponytails in the phosphine core for the rhodium-catalyzed hydroformylation of styrene (Scheme 7.14). The branched aldehyde was formed with 93.6% ee. An average TOF = 23 h was calculated. After the first run, the reaction mixture was cooled to room temperature and CO2 was partly... 

Fluoroalkyl-l -pyrazoles 58 were synthesized in excellent yields in one-pot procedure starting from polyfluoroalkyl iodides 56 [30]. The treatment of 56 wi(h ethylvinyl ether led to their corresponding fluoroalkyl aldehyde intermediates 57, which upon condensation with hydrazine acetic acid under mild conditions gave pyrazoles 58 (Scheme 17). 

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