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Mixture Synthesis of Fluorous Ketals: Mitsunobu Reaction of Homologous 3‐Perfluoroalkyl‐propanols with Hexafluoroacetone Sesquihydrate and Collective Determination of Fluorophilicity Values

2006; Wiley; Volume: 25; Issue: 8-9 Linguagem: Inglês

10.1002/qsar.200640046

1611-0218

József Rábai, Ana‐Maria Bálint, Csongor Szíjjártó, Dénes Szabó,

Analytical Chemistry and Chromatography

Abstract The reaction of hexafluoroacetone sesquihydrate ( 1 , 2 mmol) with a mixture of 3‐perfluoroalkyl‐propanols (C n F 2 n +1 (CH 2 ) 3 OH; 2a – d : n =4, 6, 8, 10; 1 mmol each) in an ether solution using the classical Ph 3 P/diisopropyl azodicarboxylate reagent pair afforded a mixture of ten ketals [(CF 3 ) 2 C(O(CH 2 ) 3 C n F 2 n +1 ) 2 , 3 { a – d }×{ a – d }]. The mixture of the ten fluorophilic ketals was easily separated from side products using fluorous extraction (FC‐72/CH 3 OH). The composition of this fluorous ketal mixture was quantitatively analyzed by GC, and the results obtained were in agreement with predictable trends based on a statistical model. A method for collective fluorophilicity determination of the individual fluorous ketals was supplemented with the calculation of fluorous isotherms and the analysis of gas chromatographic elution orders.