Faculty Profiles - OOI Takashi

Papers - OOI Takashi

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Practical Asymmetric Synthesis of Vicinal Diamines Through the Catalytic Highly Enantioselective Alkylation of Glycine Amide Derivatives. Reviewed

Ooi, Takashi; Sakai, Daiki; Takeuchi, Mifune; Tayama, Eiji; Maruoka, Keiji

Angew. Chem., Int. Ed. Vol. 42 page： 5868-5870 2003

A New N-Spiro C2-Symmetric Chiral Quaternary Ammonium Bromide Consisting of 4,6-Disubstituted Biphenyl Subunit as an Efficient Chiral Phase-Transfer Catalyst. Reviewed

Ooi, Takashi; Kubota, Yasushi; Maruoka, Keiji

Synlett page： 1931-1933 2003

Language：English Publishing type：Research paper (scientific journal)

A new N-spiro chiral quaternary ammonium bromide has been designed and assembled from optically active 4,6-disubstituted biphenyl subunits. Its utility as an efficient chiral phase-transfer catalyst has been clearly demonstrated by application to the highly enantioselective alkylation of tert-butyl glycinate benzophenone Schiff base.

Corrigendum:Highly Enantioselective Construction of Quaternary Stereocenters on β-Keto Esters by Phase-Transfer Catalytic Asymmetric Alkylation and Michael Reaction. Reviewed

Ooi, Takashi; Miki, Takashi; Taniguchi, Mika; Shiraishi, Misato; Takeuchi, Mifune; Maruoka, Keiji

Angew. Chem., Int.l Ed. Vol. 42 page： 3796-3798 2003

A Scalable Synthesis of (R)-3,5-Dihydro-4H-dinaphth[2,1-c:1'2'-e]azepine. Reviewed

Ikunaka, Masaya; Maruoka, Keiji; Okuda, Yoshiaki; Ooi, Takashi

Org. Proc. Res. Dev. Vol. 7 page： 644-648 2003

Language：English Publishing type：Research paper (scientific journal)

Environmentally benign scalable procedures are developed to supply enantiomerically pure (R)-3,5-dihydro-4H-dinaphth[2,1-c:1'2'-e]azepine 1 as its hydrogen oxalate salt in a five-step overall yield of 41%, which consist of the following: (1) bis O-triflation of (R)-1,1'-bi-2-naphthol 8 [(CF3SO2)2O, pyridine, PhMe; quantitative yield]; (2) Kumada's cross-coupling [MeMgI, NiCl2(dppp), tert-BuOMe; 96% yield]; (3) radical bromination [N-bromosuccinimide, 2,2'-azobisisobutyronitrile, cyclohexane; 54% yield]; (4) cyclization [allylamine, Et3N, THF, 86%]; (5) N-deallylation [1,3-dimethylbarbituric acid, Pd(OAc)2, Ph3P, PhMe] followed by crystalline salt formation with oxalic acid (overall 92% yield).

New, Improved Procedure for the Synthesis of Structurally Diverse N-Spiro C2-Symmetric Chiral Quaternary Ammonium Bromides. Reviewed

Ooi, Takashi; Uematsu, Yukitaka; Maruoka, Keiji

J. Org. Chem. Vol. 68 page： 4576-4578 2003

Language：English Publishing type：Research paper (scientific journal)

Selective, direct ortho magnesiation of (S)-2,2'-bis(isopropoxycarbonyl)-1,1'-binaphthyl (6) has been achieved under mild conditions, using magnesium bis(2,2,6,6-tetramethylpiperamide) [Mg(TMP)2]. In combination with the subsequent reaction with the appropriate electrophiles, bromine and iodine, this method constitutes a key step in establishing a new and concise synthetic route to a wide variety of N-spiro C2-symmetric chiral quaternary ammonium bromides of type 1.

Isopropoxyaluminum 1,1'-Biphenyl-2-oxy-2'-perfluorooctanesulfonamide as a Catalyst for Tishchenko Reaction. Reviewed

Ooi, Takashi; Ohmatsu, Kohsuke; Sasaki, Kouji; Miura, Tomoya; Maruoka, Keiji

Tetrahedron Lett. Vol. 44 page： 3191-3193 2003

Language：English Publishing type：Research paper (scientific journal)

Isopropoxyaluminum 1,1′-biphenyl-2-oxy-2′-perfluorooctanesulfonamide (3) has been evaluated as an aluminum-based catalyst for the Tishchenko reaction. Compound 3 was found to exert high catalytic activity in the reaction with aliphatic aldehydes and also enabled smooth dimerization of enolizable aldehydes. This advantage was highlighted by the quantitative formation of ethyl acetate from acetaldehyde by the present system.

Highly Stereoselective N-Terminal Functionalization of Small Peptides by Chiral Phase-Transfer Catalysis. Reviewed

Ooi, Takashi; Tayama, Eiji; Maruoka, Keiji

Angew. Chem., Int. Ed. Vol. 42 page： 579-582 2003

Designer Chiral Quaternary Ammonium Bifluorides as an Efficient Catalyst for Asymmetric Nitroaldol Reaction of Silyl Nitronates with Aromatic Aldehydes. Reviewed

Ooi, Takashi; Doda, Kanae; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 125 page： 2054-2055 2003

Language：English Publishing type：Research paper (scientific journal)

Designer chiral quaternary ammonium bifluoride 1 has been prepared, and both its catalytic and its chiral efficiency have been clearly demonstrated by achieving the first catalytic asymmetric nitroaldol reaction of silyl nitronate with aldehydes. For instance, the reaction of trimethylsilyl nitronate 2 (R1 = Me) with benzaldehyde (R2 = Ph) in THF in the presence of (S,S)-1 (2 mol %) proceeded smoothly at -78 C, giving the corresponding nitroaldol adduct 3 (R1 = Me, R2 = Ph) in 92% isolated yield (anti/syn = 92:8) with 95% ee (anti isomer). The method was found to be successfully applicable to other aromatic aldehydes and silyl nitronates, and a high level of anti selectivity and enantiomeric excess was constantly observed. This finding should lead to the further development of fluoride ion-catalyzed asymmetric carbon-carbon bond-forming reactions.

Asymmetric Skeletal Rearrangement of Symmetrically α,α-Disubstituted α-Amino Aldehydes: A New Entry to Optically Active α-Hydroxy Ketones. Reviewed

Ooi, Takashi; Saito, Akira; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 125 page： 3220-3221 2003

Language：English Publishing type：Research paper (scientific journal)

A unique asymmetric skeletal rearrangement of symmetrically ,-disubstituted -amino aldehydes has been accomplished for the first time using a chiral organoaluminum Lewis acid 1. For instance, treatment of (S)-2,2'-bis(trifluoromethanesulfonylamino)-1,1'-binaphthyl with Me3Al (1.0 equiv) in toluene at room temperature for 15 min and at 110 C for an additional 15 min produced (S)-1, and a subsequent reaction with -amino aldehyde 2a (R = CH2Ph) at -78 C for 4 h and at -40 C for 12 h resulted in the smooth rearrangement to the zwitterionic iminium intermediate A, which furnished the -hydroxy ketone 3a (R = CH2Ph) in 93% isolated yield with 95% ee (S) after acidic hydrolysis. This result, together with other representative examples, clearly demonstrates the effectiveness of the present method for the hitherto difficult asymmetric synthesis of acyloins. Furthermore, we found that the treatment of the in situ generated A with DIBAH afforded the corresponding anti amino alcohol exclusively without loss of enantiomeric excess. Our approach casts light on the previously unexplored yet potential utility of -amino aldehydes as synthetic building blocks and also provides a new entry to optically active -hydroxy ketones and 1,2-amino alcohols.

Design of N-Spiro C2-Symmetric Chiral Quaternary Ammonium Bromides as Novel Chiral Phase-Transfer Catalysts: Synthesis and Application to Practical Asymmetric Synthesis of α-Amino Acids. Reviewed

Ooi, Takashi; Kameda, Minoru; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 125 page： 5139-5151 2003

Language：English Publishing type：Research paper (scientific journal)

A series of C2-symmetric chiral quaternary ammonium bromides 10 and 11 have been designed as a new, purely synthetic chiral phase-transfer catalyst, and readily prepared from commercially available optically pure 1,1'-bi-2-naphthol as a basic chiral unit. The details of the synthetic procedures of each requisite chiral binaphthyl subunit have been disclosed, and the structures of the assembled N-spiro chiral quaternary ammonium bromides 11a and 11f were unequivocally determined by single-crystal X-ray diffraction analysis. The reactivity and selectivity of these chiral ammonium bromides as chiral phase-transfer catalysts have been evaluated in the asymmetric alkylation of the benzophenone Schiff base of glycine ester 7 under mild liquid-liquid phase-transfer conditions, and the optimization of the reaction variables (solvent, base, and temperature) has also been conducted. Further, the scope and limitations of this asymmetric alkylation have been thoroughly investigated with a variety of alkyl halides, in which the advantage of the unique N-spiro structure of 11 and dramatic effect of the steric as well as the electronic properties of the aromatic substituents on the 3,3'-position of one binaphthyl moiety have been particularly emphasized. Finally, the potential synthetic utility of the present method for the practical asymmetric synthesis of structurally diverse natural and unnatural -amino acids has been demonstrated by its successful application to the facile asymmetric syntheses of (S)-N-acetylindoline-2-carboxylate, a key intermediate in the synthesis of the ACE inhibitor, and L-Dopa (L-3,4-dihydroxyphenylalanine) ester and its analogue.

Enantioselective synthesis of α-amino acids by chiral phase-transfer catalysis. Reviewed

Ooi, Takashi; Maruoka, Keiji

Yuki Gosei Kagaku Kyokaishi Vol. 61 page： 1195 2003

Enantioselective Amino Acid Synthesis by Chiral Phase-Transfer Catalysis. Reviewed

Maruoka, Keiji; Ooi, Takashi

Chem. Rev. Vol. 103 page： 3013-3028 2003

Asymmetric Induction in the Neber Rearrangement of Simple Ketoxime Sulfonates under Phase-Transfer Conditions: Experimental Evidence for the Participation of an Anionic Pathway. Reviewed

Ooi, Takashi; Takahashi, Makoto; Doda, Kanae; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 124 page： 7640-7641 2002

Language：English Publishing type：Research paper (scientific journal)

Phase-transfer catalysis has been successfully utilized for the Neber rearrangement of simple ketoxime sulfonates. For instance, treatment of (Z)-1a with p-toluenesulfonyl chloride (1.2 equiv), tetrabutylammonium bromide (5 mol %) and MeOH (10 equiv) in toluene-50% KOH aqueous solution (volume ratio = 3:1) at 0 C for 2 h, and subsequent benzoylation followed by acidic hydrolysis afforded the protected -amino ketone 2a in 80% isolated yield. On the basis of this finding, asymmetric Neber rearrangement with ketoxime (Z)-1a was examined under phase-transfer conditions using structurally rigid, C2-symmetric chiral quaternary ammonium bromide 3 as catalyst. The desired 2a was obtained in 80% yield and 51% ee. This represents the first experimental demonstration of the substantial involvement of anion pathway in the Neber rearrangement of simple ketoxime sulfonates. Importantly, the reaction with (E)-1a under otherwise similar conditions afforded racemic 2a in 61% yield. Moreover, enhanced enantioselectivity (63% ee) was observed in the rearrangement of the oxime sulfonate derived from (Z)-1b, and notably, use of mesitylene in place of toluene further increased the enantioselectivity to 70% ee. Our approach provides not only a new mechanistic insight but also an opportunity for extending the full synthetic utility of this classical yet useful rearrangement.

Conformationally Flexible, Chiral Quaternary Ammonium Bromides for Asymmetric Phase-Transfer Catalysis. Reviewed

Ooi, Takashi; Uematsu, Yukitaka; Kameda, Minoru; Maruoka, Keiji

Angew. Chem., Int. Ed. Vol. 41 page： 1551-1554 2002

Practical Approach to the Meerwein-Ponndorf-Verley Reduction of Carbonyl Substrates with New Aluminum Catalysts. Reviewed

Ooi, Takashi; Ichikawa, Hayato; Maruoka, Keiji

Angew. Chem., Int. Ed. Vol. 40 page： 3610-3612 2001

"Amphiphilic" Cleavage of γ-Stannyl Ketones with ATPH/RLi: Application to Enone Fragmentation by the Conjugate Addition-Cleavage Sequence. Reviewed

Kondo, Yuichiro; Kon-i, Kana; Iwasaki, Atsuko; Ooi, Takashi; Maruoka, Keiji

Angew. Chem., Int. Ed. Vol. 39 page： 414-416 2000

Practical Catalytic Enantioselective Synthesis of α,α-Dialkyl-α-amino Acids by Chiral Phase-Transfer Catalysis. Reviewed

Ooi, Takashi; Takeuchi, Mifune; Kameda, Minoru; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 122 page： 5228-5229 2000

Chemistry of chelate-type hypervalent boron and aluminum. Utilization for selective organic synthesis. Reviewed

Uraguchi, Daisuke; Ooi, Takashi; Maruoka, Keiji

Yuki Gosei Kagaku Kyokaishi Vol. 58 page： 14-22 2000

「光学活性相間移動触媒が拓く有機合成−二相系での実用的不斉合成プロセス」 Invited

亀田　稔, 大井　貴史, 丸岡　啓二

化学 Vol. 55 page： 70-71 2000

The Synthetic Utility of the Hypercoordination of Boron and Aluminum. Invited Reviewed

Maruoka, Keiji; Ooi, Takashi.

Chem. Eur. J. Vol. 5 page： 829-833 1999

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