Super fluorous

S. Hadida, M. S. Super, E. J. Beckman, D. P. Curran, Radical Reactions with Alkyl and Fluoroalkyl (Fluorous) Tin Hybride Reagents in Supercritical C02 , J. Am. Chem. Soc 1997,119,7406. 

Abiotic environments— super-nonpolar fluorous compartments for... 

Hadida S, Super MS, Beckman EJ, Curran DP, Radical reactions with alkyl and fluoroalkyl (fluorous) tin hydride reagents in supercritical C02, J. Am. Chem. Soc., 119 7406-7407, 1997. 

We have developed a fluorous super-Bronsted acid catalyst, 4-(lH,lH-perfluoro-tetradecanoxy)-2,3,5,6-tetra Luorophenylbis(trifluoromethanesulfonyl)methane (8), which can be recycled by applying liquid/solid phase separation without fluorous solvents [8] and an organic-solvent-swellable resin-bound super-Br0nsted acid, polystyrene-bound tetrafluorophenylbis(trifluoromethanesulfonyl)methane (9) [9]. 

The acetalization of benzaldehyde with 1,3-propanediol has been examined in the presence of 1 mol% of a fluorous super-Br0nsted acid, 13 or 8, at azeotropic reflux in cyclohexane with the removal of water for 3 h [Eq. (6)]. Both solid acids are soluble in cyclohexane under reflux conditions, and promote the reaction well to give the desired acetal in good yields. Post-reaction, 13 has been recovered in 96% yield by precipitation at room temperature. However, 13 can not be recovered in the same manner. Besides this acetalization, 8 is also effective as a fluorous catalyst for the acylation of l-menthol with benzoic anhydride [Eq. (7)] and esterification of 3-phenylpropionic acid in methanol [Eq. (8)] [11]. 

Mikami s group has also demonstrated the advantage of the fluorous super-Lewis acids such as lanthanide tris(perfluorooctanesulfonyl)methide and perfluorooctane-sulfonimide complexes with respect to temperature-dependent solubility [13bj. For example, these complexes can be re-used for the Friedel-Crafts acylation reaction without fluorous solvents [Eq. (11)]. After the reaction mixture of anisole has been heated with acetic anhydride in 1,2-dichloroefhane in the presence of ytterbium perfluorooctanesulfonimide (10 mol%) at 80 °C for 6 h, the mixture is allowed to stand at -20 °C for 30 min to precipitate the ytterbium complex. The liquid phase is decanted and the residual lanthanide complex is re-used without isolation. No loss of activity is observed for the catalyst recovered. The total isolated yield of the product, which is combined from the three runs, is 78%. 

The two following examples incorporate the fluorous super Brpnsted acid catalyst 13 for the acetalization of benzaldehyde with 1,3-propanediol and for the... 

Lecture 15-18 solvents - water, liquid carbon dioxide, super-critical water, super-critical carbon dioxide, fluorous solvents, deep eutectics, ionic liquids Lecture 19 renewable feedstocks... 

Ishihara K, Hasegawa A, Yamamoto H (2002) A fluorous super Br0nsted acid catalyst application to fluorous catalysis with fluorous solvents. Synlett 8 1299-1301... 

At the same time, they developed fluorous super Brousted acid by nucleophilic para substitution of the lithium salt of pentafluorophenylbis(triflyl)methane with... 

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