Methyl perfluorobutyrate

In 2001, Hitachi, Ltd. discovered that fluorinated alkyl esters, such as methyl perfluorobutyrate (150), can be used as additives in small quantities [145]. 

Abbreviations acac, acetylacetonate acam, acetamide, BINAP, binaphtholphosphate BN OX, 4-benzyl-2-oxazolidinone cap, caprolactamate DM AD, dimethyl acetylenedicarboxy-late hfacac, hexafluoroacetylacetonate MACIM, methyl l-acetylimidazolidin-2-one-4-carboxylate MEPY, methyl 2-pyrrolidone-5-carboxylate MEOX, methyl 2-oxazolidinone-4-carboxylate NPMI, A-phenylmaleimide pfb, perfluorobutyrate oct, octanoate TEBA, benzyltriethylammonium chloride tfa, trifluoroacetamidate. 

There are several examples of catalyzed aromatic cycloadditions leading to heterocyclic systems. The rhodium(II) acetate-catalyzed intramolecular Buchner reactions of iV-benzyldiazoacetamides 64a/b afford azabicyclo[5.3.0]decatrienes 66a/b in excellent yields. In contrast, the N-methyl derivative 64c gives 66c in moderate yield. Use of rhodium(II) perfluorobutyrate (Rh2(pfb)4) in place of rhodium(II) acetate increases the yield to 54%. Unlike its carbon counterpart, dihydroazulenone 29a (vide supra), 66a is insensitive to either trifluoroacetic acid or boron trifluoride etherate, even in excess, and the unrearranged reactant is recovered intact even after prolonged treatment at room temperature. 

The known tricyclic olefin 193 was oxidatively ring opened at the olefinic ring to give an indoline derivative which was transformed to the starting prerequisite diazo imide 194. The rhodium-catalyzed reaction of 194 proceeded smoothly, using rhodium(II) perfluorobutyrate as the catalyst, to give the cycloadduct 195 as the exclusive product in 93% yield. The conversion of the cycloadduct 195 to methyl paspalate was undertaken by treating 195 with... 

Perfluoroammonium octanoate. See Ammonium perfluorooctanoate (Perfluoro-n-butyl) methyl ether. See Methyl nonafluorobutyl ether Perfluorobutyric acid. See Heptafluorobutyric acid Perfluorocaprylic acid. See Perfluorooctanoic acid Perfluorocaprylic acid ammonium saK. See Ammonium perfluorooctanoate Perfluoroctanoic acid. See Perfluorooctanoic acid Perfluoroethylene propylene. See Fluorinated ethylene/propylene Perfluoroheptane... 

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