研究者詳細 - 大井　貴史

論文 - 大井　貴史

分割表示 203 件中 121 - 140 件目／全件表示 >>

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

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

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 47 巻 ( 28 ) 頁： 5203-5206 2008年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

Synthesis of Chiral Tetraaminophosphonium Chlorides from N-BOC α-Amino Acid Esters 招待有り査読有り

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

Heterocycles 76 巻頁： 1081-1085 2008年

*Chiral Tetraaminophosphonium Carboxylate-Catalyzed Direct Mannich-Type Reaction 査読有り

Uraguchi, Daisuke; Ueki, Yusuke; Ooi, Takashi

J. Am. Chem. Soc. 130 巻頁： 14088–14089 2008年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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招待有り

浦口大輔、大井貴史

化学 63 巻頁： 66-67 2008年

Recent advances in asymmetric phase-transfer catalysis 査読有り

Ooi, Takashi; Maruoka, Keiji

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 46 巻 ( 23 ) 頁： 4222-4266 2007年

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

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

Org. Lett. 9 巻 ( 20 ) 頁： 3945-3948 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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

Ooi, Takashi; Ohmatsu, Kohsuke; Maruoka, Keiji

J. Am. Chem. Soc. 129 巻頁： 2410-2411 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

Development and Applications of C2-Symmetric, Chiral, Phase-Transfer Catalysts 招待有り査読有り

Ooi, Takashi; Maruoka, Keiji

Aldrichimia Acta 40 巻頁： 77-86 2007年

*Chiral Tetraaminophosphonium Salt-Mediated Asymmetric Direct Henry Reaction 査読有り

Uraguchi, Daisuke; Sakaki, Sawako; Ooi, Takashi

J. Am. Chem. Soc. 129 巻頁： 12392-12393 2007年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

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.

Design of chiral organocatalysts for practical asymmetric synthesis of amino acid derivatives 招待有り査読有り

Maruoka, Keiji; Ooi, Takashi; Kano, Taichi

CHEMICAL COMMUNICATIONS ( 15 ) 頁： 1487-1495 2007年

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

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

Tetrahedron Lett. 48 巻頁： 1337-1340 2007年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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

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

Angew. Chem., Int. Ed. 45 巻頁： 7606-7608 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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

Ooi, Takashi; Uematsu, Yukitaka; Maruoka, Keiji

J. Am. Chem. Soc. 128 巻頁： 2548-2549 2006年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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

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

Tetrahedron 62 巻頁： 11425-11436 2006年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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. 17 巻頁： 603-606 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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

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

Adv. Synth. Catal. 348 巻頁： 1539-1542 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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

Takashi, Ooi; Kazuhiro, Fukumoto; Keiji, Maruoka

Angew. Chem., Int. Ed. 45 巻頁： 3839-3842 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

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. 査読有り

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

J. Am. Chem. Soc. 127 巻頁： 5073-5083 2005年

記述言語：英語掲載種別：研究論文（学術雑誌）

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.

Asymmetric Synthesis of Functionalized Aza-Cyclic Amino Acids with Quaternary Stereocenters by a Phase-Transfer-Catalyzed Alkylation Strategy. 査読有り

Ooi, Takashi; Miki, Takashi; Maruoka, Keiji

Org. Lett. 7 巻頁： 191-193 2005年

記述言語：英語掲載種別：研究論文（学術雑誌）

Practical asymmetric synthesis of functionalized aza-cyclic -amino acid derivatives possessing quaternary stereocenters has been achieved by the phase-transfer-catalyzed alkylation of 2 or 3 using chiral quaternary ammonium bromide 1 as catalyst. Subsequent reduction and alkylation of the 3-keto carbonyl moiety of 4 proceeded with complete diastereochemical control to afford the corresponding -hydroxy aza-cyclic -amino acid derivatives having stereochemically defined consecutive quaternary carbon centers.

Dramatic Rate Enhancement of Asymmetric Phase-Transfer-Catalyzed Alkylations. 査読有り

Shirakawa, Seiji; Yamamoto, Kenichiro; Kitamura, Masanori; Ooi, Takashi; Maruoka, Keiji

Angew. Chem., Int. Ed. 44 巻頁： 625-628 2005年

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