Dynamic Stereochemical Control by Using Lewis Acid Base Active Species

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In this research project, we focused our attention on the design of truly important synthetic catalysts for the development of Lewis acid/base active species in order to achieve the highly selective stereochemical control. Namely, Maruoka studied unprecedented chelate-type pentacoordinate boron complexes and the bidentate Lewis acid chemistry. In the latter chemistry, a new, chiral bidentate Ti (IV) complex 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. Ooi prepared (2,7-dimethyl-1,8-biphenylenedioxy)bis(dimethylaluminum) and (anthraquinone-1,8-dioxy)bis(triisopropoxytitanium) as bidentate Lewis acids for the simultaneous coordination to carbonyl substrates. The high, simultaneous coordination ability of the bidentate organoaluminum and titanium reagents toward carbony … More ls is emphasized in comparison with the corresponding monodentate reagents, and characterized by evaluating the double electrophilic activation of ketonic substrates in several electrophilic reactions. Kakuchi used the ring polymerization of 1,2 : 4,5-dianhydropentitol for the application to the chiral stationary phases and the elucidation of the optical resolution mechanism of amino acids. Inanaga designed chiral rare-earth metal complexes as thermodynamically stable, single active species for applying asymmetric transformations. Uemura developed the Friedel-Crafts-type reactions of alkenes and the oxidation reactions of alcohols by using metal cation-exchanged montmorillonite catalysts. Shionoya synthesized a novel nucleoside for alternative DNA base pairing through metal complexation, and carried out the molecular recognition of terephthalic acids by supramolecular self-assembly of acridine-pendant Zn(II)-cyclen complex. Tomooka developed the enantioselective carboanion reactions and the enantioselective radical reactions for effecting the dynamic stereochemical control of organolithium species. Less