Joji Nishikido

Lanthanide catalysts with tris(perfluorooctanesulfonyl)methide and bis(perfluorooctanesulfonyl)amide ponytails: recyclable Lewis acid catalysts in fluorous phases or as solids☆

Abstract Lanthanide tris(perfluorooctanesulfonyl)methide and bis(perfluorooctanesulfonyl)amide complexes are shown to be immobilized and continuously recycled in fluorous phases or as solids. The lanthanide complexes are thus extremely efficient Lewis acid catalysts for carbon–carbon bond forming (CCF) reactions. The CCF reactions such as the Friedel–Crafts acylation, Diels–Alder, and Mukaiyama aldol reaction are effectively catalyzed by the lanthanide complexes by virtue of the highly electron-withdrawing effect of tris(perfluorooctanesulfonyl)methide and bis(perfluorooctanesulfonyl)amide ponytails without any hydrocarbon spacer.

Lewis acid catalysis by lanthanide complexes with tris(perfluorooctanesulfonyl)methide ponytails in fluorous recyclable phase

Abstract Scandium and ytterbium tris(perfluorooctanesulfonyl)methide complexes are shown to be immobilized in fluorous recyclable phase and extremely efficient Lewis acid catalysts for alcohol acylation, Friedel–Crafts acylation, Diels–Alder reaction, and Mukaiyama aldol reaction by virtue of the highly electron-withdrawing effect of tris(perfluorooctanesulfonyl)methide ponytails without any hydrocarbon spacer.

Tin(IV) bis(perfluoroalkanesulfonyl)amide complex as a highly selective Lewis acid catalyst for Baeyer–Villiger oxidation using hydrogen peroxide in a fluorous recyclable phase

Abstract Sn[N(SO 2 C 8 F 17 ) 2 ] 4 catalyst was shown to give an excellent yield and selectivity in a fluorous biphasic catalytic system for Baeyer–Villiger oxidation of cyclic ketones by 35% aqueous hydrogen peroxide, a green, safe and cheap oxidant. Furthermore, the catalyst was completely recovered and reused in the fluorous immobilized phase without loss of activity.

Recyclable Lewis acid catalysts by tuning supercritical vs liquid carbon dioxide phases: lanthanide catalysts with tris(perfluorooctanesulfonyl)methide and bis(perfluorooctanesulfonyl)amide

Lanthanide tris(perfluorooctanesulfonyl)methide and bis(perfluorooctanesulfonyl)amide catalysts are shown to be continuously employed in supercritical carbon dioxide by changing supercritical vs. liquid carbon dioxide phases. The lanthanide complexes are thus extremely efficient Lewis acid catalysts even in supercritical carbon dioxide phase by virtue of the highly electron-withdrawing and solubilizing effect of tris(perfluorooctanesulfonyl)methide and bis(perfluorooctanesulfonyl)amide without any hydrocarbon spacer.

Development of the continuous-flow reaction system based on the Lewis acid-catalysed reactions in a fluorous biphasic system

Lanthanide(III) bis(perfluoroalkanesulfonyl)amide-catalysed reactions such as esterification and Baeyer–Villiger reactions in organic-fluorous biphase were performed to yield products with high TONs using the continuous-flow system of the small- and bench-scale apparatus which consisted of a reactor with a mechanical stirrer and a decanter. In the novel continuous-flow system, the Lewis acid catalyst is immobilised in a fluorous solvent while the substrates and the products obtained are dissolved in the mobile organic phase.

Green Baeyer–Villiger oxidation with hydrogen peroxide: Sn[N(SO2C8F17)2]4 as a highly selective Lewis acid catalyst in a fluorous biphase system

In a fluorous biphasic catalytic system for Baeyer–Villiger oxidation of cyclic ketones, it was shown that Sn[N(SO2C8F17)2]4 catalyst can give an excellent yield and selectivity with the green, safe and cheap 35% aqueous hydrogen peroxide as the oxidant. Furthermore, it was also found that the catalyst can be completely recovered and reused without loss of its activity in the fluorous immobilized phase.

Hf[N(SO2C8F17)2]4 as a highly active and recyclable Lewis acid catalyst for direct esterification of methacrylic acid with methanol in a fluorous biphase system

The activity of Hf[N(SO2C8F17)2]4 catalyst for the direct esterification of methacrylic acid with methanol was studied and compared with representative acid catalysts including the present industrially employed H2SO4 and Nafion® SAC-13. It was found that Hf[N(SO2C8F17)2]4 in a fluorous biphase system (FBS) is most effective based on initial rate analysis and yield. In the simulated industrial solution (the reaction mixture was preliminarily doped with H2O, H2O/MAA = 1.6 mmol), the initial rate with Hf[N(SO2C8F17)2]4 was shown to be about 9 times that with H2SO4. Meanwhile, an excellent yield (86%) and selectivity (97%) were obtained with Hf[N(SO2C8F17)2]4, which are superior to the other evaluated catalysts. Furthermore, the immobilized fluorous phase was completely recovered and reused without loss of its catalytic activity either in the simulated industrial solution (both with and without preliminarily doping with H2O) or in the practical industrial solution.