Satoshi Kii

Practical approach for catalytic asymmetric allylation of aldehydes with a chiral bidentate titanium(IV) complex

A new, chiral bidentate Ti(IV) complex of type 1 was successfully designed and can be utilized for simultaneous coordination to aldehyde carbonyls, thereby allowing the precise enantioface discrimination of such carbonyls for a new catalytic, practical enantioselective allylation of aldehydes with allyltributyltin.

Bis-zirconium and bis-hafnium catalysts for the strong activation of carbonyl substrates

Abstract (3,3′-Di- t -butyl-5,5′-dimethylbenzophenone-2,2′-dioxy)bis(triisopropoxyzirconium) and its hafnium derivative can be successfully utilized in organic synthesis as bimetallic Lewis acid catalysts. The high activation ability of such catalysts toward carbonyls is emphasized using several synthetic examples including the asymmetric allylation in comparison with the corresponding mono-Zr as well as bis-Ti catalysts.

Simultaneous coordination and double activation phenomena of carbonyl and epoxy oxygens by bis-titanium reagent as a bidentate Lewis acid catalyst

Abstract The new bidentate Ti catalyst, (anthraquinone-1,8-dioxy)bis(triisopropoxy-titanium) ( 1 ) can be successfully designed and utilized for the simultaneous coordination to carbonyl substrates. The high double-activation ability of the bidentate Ti catalyst 1 toward carbonyls is emphasized using several synthetic examples in comparison with the corresponding monodentate Ti catalyst. The intermediary coordination complex formation of bidentate 1 with DMF or epoxycyclohexane as a carbonyl or epoxy substrate is characterized by 13 C NMR spectroscopy.