Faculty Profiles - OOI Takashi

Papers - OOI Takashi

Division display 121 - 140 of about 203 ／ All the affair displays >>

Complete Switch of Migratory Aptitude in Aluminum-Catalyzed 1,2-Rearrangement of Differently α,α-Disubstituted α-Siloxy Aldehydes Reviewed

Ohmatsu, Kohsuke; Tanaka, Takayuki; Ooi, Takashi; Maruoka, Keiji

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 47 ( 28 ) page： 5203-5206 2008.6

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

Regiodivergent 1,2-rearrangement of alpha-siloxy aldehydes bearing alpha-aryl and alpha-alkyl substituents into alpha-siloxy ketones has been realized by using different Al Lewis acid catalyst/solvent systems. The scope of this unprecedented protocol has been investigated with various substrates, clearly demonstrating its utility for the selective synthesis of two structural isomers from one substrate.

DOI： 10.1002/anie.200800801

Synthesis of Chiral Tetraaminophosphonium Chlorides from N-BOC α-Amino Acid Esters Invited Reviewed

Uraguchi, Daisuke; Sakaki, Sawako; Ueki, Yusuke; Ito, Takaki; Ooi, Takashi

Heterocycles Vol. 76 page： 1081-1085 2008

*Chiral Tetraaminophosphonium Carboxylate-Catalyzed Direct Mannich-Type Reaction Reviewed

Uraguchi, Daisuke; Ueki, Yusuke; Ooi, Takashi

J. Am. Chem. Soc. Vol. 130 page： 14088–14089 2008

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The cooperative asymmetric catalysis of chiral tetraaminophosphonium carboxylate (P,S)-1·OCOR has been established, and its synthetic utility has been successfully demonstrated by application to the highly enantioselective direct Mannich-type reaction of azlactones with N-sulfonyl imines. The present study stimulates the cultivation of the potential of the chiral quaternary onium salt catalysis by the structural modification of organic anion.

DOI： 10.1021/ja806311e

光学活性な炭素の三角形を作る―Corey-Chaykovsky反応と親電子剤活性化法の組み合わせ Invited

浦口大輔、大井貴史

化学 Vol. 63 page： 66-67 2008

Recent advances in asymmetric phase-transfer catalysis Reviewed

Ooi, Takashi; Maruoka, Keiji

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 46 ( 23 ) page： 4222-4266 2007

Development and Applications of C2-Symmetric, Chiral, Phase-Transfer Catalysts Invited Reviewed

Ooi, Takashi; Maruoka, Keiji

Aldrichimia Acta Vol. 40 page： 77-86 2007

*Chiral Tetraaminophosphonium Salt-Mediated Asymmetric Direct Henry Reaction Reviewed

Uraguchi, Daisuke; Sakaki, Sawako; Ooi, Takashi

J. Am. Chem. Soc. Vol. 129 page： 12392-12393 2007

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A chiral tetraaminophosphonium salts possessing the phosphorus-centered [5.5]-spirocyclic core have been designed and synthesized in a single step from L-valine-derived diamine. The three-dimensional molecular structure was successfully verified by the single-crystal X-ray diffraction analysis, which also identified a secondary interaction between the phosphonium cation and chloride ion via double hydrogen-bonding. The potential of this novel onium salt as a chiral organic molecular catalyst has been demonstrated in an application to asymmetric direct Henry reaction.

DOI： 10.1021/ja075152+

Design of chiral organocatalysts for practical asymmetric synthesis of amino acid derivatives Invited Reviewed

Maruoka, Keiji; Ooi, Takashi; Kano, Taichi

CHEMICAL COMMUNICATIONS ( 15 ) page： 1487-1495 2007

Catalytic Asymmetric Rearrangement of α,α-Disubstituted α-Siloxy Aldehydes to Optically Active Acyloins Using Axially Chiral Organoaluminum Lewis Acids Reviewed

Ooi, Takashi; Ohmatsu, Kohsuke; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 129 page： 2410-2411 2007

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

A catalytic asymmetric rearrangement of alpha,alpha-dialkyl-alpha-siloxy aldehydes has been developed based on the design of a stereochemically defined, axially chiral organoaluminum Lewis acid. The scope of this unprecedented stereoselective rearrangement has been investigated with representative substrates, in which impressive kinetic resolution of racemic, alpha,alpha-disubstituted alpha-siloxy aldehydes has also been achieved. These results clearly demonstrate the utility of the present approach for the catalytic enantioselective synthesis of various acyloins and tertiary alpha-hydroxy aldehydes not readily accessible by the previously known asymmetric methodologies.

DOI： 10.1021/ja063051q

Advantage of in situ generation of N-arylsulfonyl imines from α-amide sulfones in the phase-transfer-catalyzed asymmetric Strecker reaction Reviewed

Ooi, Takashi; Uematsu, Yukitaka; Fujimoto, Jun; Fukumoto, Kazuhiro; Maruoka, Keiji

Tetrahedron Lett. Vol. 48 page： 1337-1340 2007

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Highly efficient, catalytic enantioselective synthesis of N-arylsulfonyl α-amino nitriles from the corresponding α-amido sulfones has been achieved under toluene–aqueous potassium cyanide biphasic conditions using chiral quaternary ammonium iodide (R,R,R)-1 as an effective phase-transfer catalyst. This Strecker synthesis involving the in situ generation of the reactive N-sulfonyl imines is advantageous for the cyanation of the substrates having primary and secondary alkyl substituents.

DOI： 10.1016/j.tetlet.2006.12.122

Practical Stereoselective Synthesis of -Branched -Amino Acids through Efficient Kinetic Resolution in the Phase-Transfer-Catalyzed Asymmetric Alkylations Reviewed

Ooi, Takashi; Kato, Daisuke; Inamura, Koji; Ohmatsu, Kohsuke; Maruoka, Keiji

Org. Lett. Vol. 9 ( 20 ) page： 3945-3948 2007

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

Phase-transfer-catalyzed alkylation of glycinate Schiff base with racemic secondary alkyl halides proceeded with excellent levels of syn- and enantioselectivities under the influence of chiral quaternary ammonium bromide 1d and 18-crown-6. The alkylation product can be selectively converted to the corresponding anti isomer, allowing the preparation of all the stereoisomers of -alkyl--amino acid derivatives, an extremely valuable chiral building block.

DOI： 10.1021/ol701558e

Highly diastereo- and enantioselective formal conjugate addition of nitroalkanes to nitroalkenes by chiral ammonium bifluoride catalysis. Reviewed

Ooi, Takashi; Takada, Saki; Doda, Kanae; Maruoka, Keiji

Angew. Chem., Int. Ed. Vol. 45 page： 7606-7608 2006

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

An efficient catalysis of new chiral quaternary ammonium bifluoride in combination with silyl nitronates has been successfully utilized for achieving the highly diastereo- and enantioselective formal conjugate addition of nitroalkanes to nitroalkenes. This unique catalytic asymmetric protocol provides a reliable access to various 1,3-dinitro compounds bearing stereochemically defined two consecutive stereocenters, which serve as a versatile chiral building block in organic synthesis.

DOI： 10.1002/anie.200602787

Asymmetric phase-transfer catalysis of homo- and heterochiral quaternary ammonium salts: development and application of conformationally flexible chiral phase-transfer catalysts. Reviewed

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

Tetrahedron Vol. 62 page： 11425-11436 2006

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Inspired by the considerable difference of catalytic activity and stereocontrolling ability between the conformationally rigid, homo- and heterochiral quaternary ammonium bromides 1, conformationally flexible, N-spiro chiral quaternary ammonium bromides of type 4 have been designed and synthesized. Reliable procedures for the preparation of the appropriately substituted biphenyl subunits have been established by the repeated use of ortho magnesiation–halogenation as a key synthetic tool. The relationship between the structure of achiral biphenyl moiety and the reactivity and selectivity of 4 has been evaluated in the asymmetric alkylation of glycinate Schiff base 2 under typical phase-transfer conditions, leading to the identification of 4l as an optimal catalyst structure to exhibit an excellent enantiocontrol in the reactions with various alkyl halides. The molecular structure of 4l was determined by X-ray crystallographic analysis and its unique behavior in solution was examined by a variable-temperature 1H NMR study. These investigations uncovered that the observed high chiral efficiency originated from the efficient asymmetric phase-transfer catalysis of homochiral-4l, which rapidly equilibrated with heterochiral-4l of low catalytic activity and stereoselectivity.

DOI： 10.1016/j.tet.2006.08.052

Asymmetric synthesis of α-acyl-γ-butyrolactones possessing all-carbon quaternary stereocenters by phase-transfer-catalyzed alkylation. Reviewed

Ooi, Takashi; Miki, Takashi; Fukumoto, Kazuhiro; Maruoka, Keiji

Adv. Synth. Catal. Vol. 348 page： 1539-1542 2006

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

The enantioselective construction of all-carbon quaternary stereocenters on -acyl--butyrolactones has been achieved by the N-spiro chiral quaternary ammonium bromide 1-catalyzed alkylation under mild phase-transfer conditions. The resulting -alkylated keto lactones serve as valuable chiral building blocks in organic synthesis as clearly demonstrated by the facile conversion to optically active ,-dialkyl--amino acid derivatives via Schmidt rearrangement.

DOI： 10.1002/adsc.200606064

Construction of Enantiomerically Enriched Tertiary α-Hydroxycarboxylic Acid Derivatives by Phase-Transfer-Catalyzed Asymmetric Alkylation of Diaryloxazolidin-2,4-diones Reviewed

Takashi, Ooi; Kazuhiro, Fukumoto; Keiji, Maruoka

Angew. Chem., Int. Ed. Vol. 45 page： 3839-3842 2006

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

Catalytic, highly enantioselective alkylation of 3,5-diaryloxazoline-2,4-diones has been accomplished under mild phase-transfer conditions using designer chiral quaternary ammonium bromide as catalyst. This catalytic asymmetric glycolate alkylation procedure establishes chiral quaternary carbon centers, and provides a practical access to various optically active tertiary alpha-hydroxy-alpha-arylcarboxylic acid derivatives.

DOI： 10.1002/anie.200600470

Highly enantioselective monoalkylation of p-chlorobenzaldehyde imine of glycine tert-butyl ester under mild phase-transfer conditions.

Ooi, Takashi; Arimura, Yuichiro; Hiraiwa, Yukihiro; Yuan, Lin Ming; Kano, Taichi; Inoue, Toru; Matsumoto, Jun; Maruoka, Keiji

Tetrahedron: Asym. Vol. 17 page： 603-606 2006

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

The selective monoalkylation of glycine tert-butyl ester aldimine Schiff base 3 has been realized in high chemical yield with excellent enantioselectivity under mild liquid–liquid phase-transfer conditions by the use of binaphthyl-derived chiral quaternary ammonium bromides 7 and 8 as catalysts. This achievement demonstrates that 3 can be used as a cost-effective substrate for the preparation of optically active α-alkyl-α-amino acid derivatives by chiral phase-transfer catalysis.

DOI： 10.1016/j.tetasy.2006.01.019

Asymmetric Strecker Reaction of Aldimines Using Aqueous Potassium Cyanide by Phase-Transfer Catalysis of Chiral Quaternary Ammonium Salts with a Tetranaphthyl Backbone. Reviewed

Ooi, Takashi; Uematsu, Yukitaka; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 128 page： 2548-2549 2006

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The phase-transfer-catalyzed, highly enantioselective cyanation of aldimines using aqueous KCN has been realized based on the molecular design of chiral quaternary ammonium iodide bearing a stereochemically defined tetranaphthyl backbone. A wide range of aliphatic aldimines, including those having -tert-alkyl substituents, is tolerated by the present system. This study represents a novel approach for the asymmetric Strecker-type reactions, which utilizes chiral phase-transfer catalysts for practical access to various unusual, optically pure -amino acids.

DOI： 10.1021/ja058066n

Highly Enantioselective Phase-Transfer-Catalyzed Alkylation of Protected α-Amino Acid Amides toward Practical Asymmetric Synthesis of Vicinal Diamines, α-Amino Ketones, and α-Amino Alcohols. Reviewed

Ooi, Takashi; Takeuchi, Mifune; Kato, Daisuke; Uematsu, Yukitaka; Tayama, Eiji; Sakai, Daiki; Maruoka, Keiji

J. Am. Chem. Soc. Vol. 127 page： 5073-5083 2005

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

Highly enantioselective alkylation of protected glycine diphenylmethyl (Dpm) amide 1 and Weinreb amide 10 has been realized under phase-transfer conditions by the successful utilization of designer chiral quaternary ammonium salts of type 4 as catalyst. Particularly, remarkable reactivity of the chiral ammonium enolate derived from 1b and 4c allowed the reaction with less reactive simple secondary alkyl halides with high efficiency and enantioselectivity. An additional unique feature of this chiral ammonium enolate is its ability to recognize the chirality of -branched primary alkyl halides, which provides impressive levels of kinetic resolution and double stereodifferentiation during the alkylation, allowing for two - and -stereocenters to be controlled. Combined with the subsequent reduction using LiAlH4 in cyclopentyl methyl ether (CPME), this system offers a facile access to structurally diverse optically active vicinal diamines. Furthermore, the optically active -amino acid Weinreb amide 11 can be efficiently converted to the corresponding amino ketone by a simple treatment with Grignard reagents. In addition, reduction and alkylation of the optically active -amino ketone into both syn and anti -amino alcohols with almost complete relative and absolute stereochemical control have been achieved. With (S,S)- and (R,R)-4 in hand, the present approach renders both enantiomers of -amino amides including Weinreb amides readily available with enormous structural variation and also establishes a general and practical route to vicinal diamines, -amino ketones, and -amino alcohols with the desired stereochemistry.

DOI： 10.1021/ja0459328

Asymmetric Michael Addition of Silyl Nitronates to Cyclic α,β-Unsaturated Ketones Catalyzed by Chiral Quaternary Ammonium Bifluorides: Isolation and Selective Functionalization of Enol Silyl Ethers of Optically Active γ-Nitro Ketones. Reviewed

Ooi, Takashi; Doda, Kanae; Takada, Saki; Maruoka, Keiji

Tetrahedron Lett. Vol. 47 page： 145-148 2005

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

Highly enantioselective Michael addition of silyl nitronates to cyclic α,β-unsaturated ketones has been accomplished by the utilization of N-spiro C2-symmetric chiral quaternary ammonium bifluoride 1 as an efficient catalyst, offering a new route to the enol silyl ethers of optically active γ-nitro ketones. The synthetic utility of this transformation has been demonstrated by the diastereoselective derivatizations of the optically active enol silyl ethers to the corresponding α-substituted cyclic ketones having three consecutive stereochemically defined stereocenters.

DOI： 10.1016/j.tetlet.2005.10.154

N-Spiro Chiral Quaternary Ammonium Bromide Catalyzed Diastereo- and Enantioselective Conjugate Addition of Nitroalkanes to Cyclic α,β-Unsaturated Ketones under Phase-Transfer Conditions. Reviewed

Ooi, Takashi; Takada, Saki; Fujioka, Shingo; Maruoka, Keiji

Org. Lett. Vol. 7 page： 5143-5146 2005

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

Conjugate addition of various prochiral nitroalkanes to cyclic ,-unsaturated ketones was found to be efficiently catalyzed by N-spiro C2-symmetric chiral quaternary ammonium bromide 1b possessing a 3,5-bis(3,4,5-trifluorophenyl)phenyl substituent under solid-liquid phase-transfer conditions to afford the corresponding -nitro ketones in excellent chemical yields with unprecedented levels of diastereo- and enantiocontrol.

DOI： 10.1021/ol0517170

　 PREV - NEXT 　

<OOI Takashi>

Papers - OOI Takashi