Takayoshi Arai

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of spirotryprostatin A led to a structure-based design of potent inhibitors by regulating the interaction between tumor suppressor p53 and E3 ubiquitin ligase MDM2. The fascinating chiral spiro[pyrrolidin-3,3’-oxindole] scaffolds have been conventionally constructed via [3+2] cycloaddition of enantiomerically enriched substrates of 2-oxoindolin-3-ylidene(More)
A library of imidazoline-aminophenol ligands was synthesized on solid supports. After immobilization of chiral chloromethylimidazolines 1 and 2 onto the polystyrylsulfonyl chloride, nucleophilic substitution with (R)- or (S)-phenylethylamine (3 and 4) provided four combinations of polymer-supported imidazoline-amine ligands. Further reductive alkylation(More)
A bis(imidazolidine)pyridine (PyBidine)-Cu(OTf)2 complex catalyzing the endo-selective [3+2] cycloaddition of nitroalkenes with imino esters was applied to the reaction of methyleneindolinones with imino esters to afford spiro[pyrrolidin-3,3'-oxindole]s in up to 98 % ee. X-ray crystallographic analysis of the PyBidine-Cu(OTf)2 complex and DFT calculations(More)
Systematic and quantitative measurements of the roles of stereochemistry and skeleton-dependent conformational restriction were made using multidimensional screening. We first used diversity-oriented synthesis to synthesize the same number (122) of [10.4.0] bicyclic products (B) and their corresponding monocyclic precursors (M). We measured the ability of(More)
The novel C(2)-symmetric bis(imidazolidine)pyridine (PyBidine) ligand was easily synthesized in a single condensation of 2,6-pyridyl aldehyde and optically active (S,S)-diphenylethylenediamine. In the C(2)-symmetric PyBidine-Cu(OTf)(2) complex, imidazolidine rings act as "chiral fences" to shield the first and third quadrants. Use of the PyBidine-Cu(OTf)(2)(More)
A catalytic asymmetric Henry reaction has been developed with use of a sulfonyldiamine-CuCl complex as a catalyst. A series of new binaphthyl-containing sulfonyldiamine ligands (2a-h) were readily synthesized in two steps starting from commercially available chiral 1,2-diamines. The (R,R)-diamine-(R)-binaphthyl ligand (2d)-CuCl complex smoothly catalyzed(More)
[reaction: see text] Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts. The polymer-supported Al-Li-bis(binaphthoxide) (ALB) catalyst was more effective than the dendrimer-supported ALB in the Michael reaction of 2-cyclohexen-1-one with dibenzyl malonate affording the adduct in 91%(More)