Yousuke Matsumoto

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.

Molecular assembly of BINOLTi complexes into an active μ3-oxo titanium catalyst

Abstract Di-μ3-oxo bridging tetranuclear titanium complex (3), obtained by exposing [Ti(OPri)2(BINOLato)] (2) to hydrated molecular sieves (MS) 4A, is a precursor of active BINOLTi catalyst (1). Further treatment of 3 with hydrated MS 4A leads to the μ3-oxo titanium cluster (1), which is the efficient asymmetric catalyst for carbonylene reactions.

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.

Optical rotation per refractive index unit, or enantiomeric (e) factor, for screening enantioselective catalysts through asymmetric activation or carbohydrates

A super high-throughput screening (SHTS) system can be constructed by combining high-performance liquid chromatography (HPLC), optical rotation (OR), and refractive index unit (RIU) to determine not only the enantioselectivity of the addition of diethylzinc to an aliphatic aldehyde catalyzed by a binaphthol-zinc complex through asymmetric activation with chiral Schiff bases, but also the enantiopurity of a carbohydrate. The enantiomeric (e) factor, which we define here as optical rotation per refractive index unit, is linearly related to the percent enantiomeric excess (%ee) and is independent of concentration.

Efficient preparation of binaphthol-derived active μ3-oxo titanium catalyst by using hydrated Na-zeolites (molecular sieves)

Abstract NaA-zeolite (MS 4A), despite a desiccant of choice, serves anomalously as an H2O donor for the titanium precatalyst and acts as a base to trap HCl to give our active binaphthol-derived titanium (BINOL-Ti) catalyst (1) for the glyoxylate-ene reaction. The active species of BINOL-Ti catalyst (1) is primarily composed of the μ3-oxo (Ti3O) species, for which the NaA-zeolite employed in the catalyst preparation acts as an H2O donor. Among zeolites with a variety of counter-cations, Na-zeolites are found to enable the quick formation of the active BINOL-Ti catalyst. A sufficient amount of sodium cations in the zeolites is critical for the efficient preparation of the active catalyst rather than the sodium content, pore size, and acid/base character based on the aluminosilicate (zeolites) frameworks.

The effect of counter cations in zeolites on the efficient preparation of the binaphthol–titanium complex

Abstract Na-zeolites, among zeolites with a variety of counter cations, are found to provide the active binaphthol–titanium catalyst for an asymmetric carbonyl-ene reaction. A sufficient content of Na cations in zeolites is the key for the efficient formation of the active catalyst.

Anomalous role of molecular sieves 4A in the preparation of abinaphthol-derived active µ3-oxo titanium catalyst

The active species of binaphthol-derived titanium catalyst 1, which is used as an efficient catalyst for glyoxylate–ene reactions, is primarily composed of a µ 3 -oxo (Ti 3 O) species, for which the molecular sieves 4A employed in the catalyst preparation act as a H 2 O donor.