- Hypercrosslinking chiral Br?nsted acids into porous organic polymers for efficient heterogeneous asymmetric organosynthesis
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Here, we developed a construction strategy for directly immobilizing the axially chiral phosphoric acid into hypercrosslinked polymers by a one-pot Friedel-Crafts alkylation reaction. The obtained chiral polymers have high porosity, excellent stability and tailorable catalytic centers, and display excellent activity, enantioselectivity and recyclability for asymmetric transfer hydrogenation.
- Jia, Ji,Liu, Xiaoming,Ma, Si,Xia, Hong,Zhang, Yuwei,Zhang, Zhenwei
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p. 25369 - 25373
(2021/12/07)
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- INHIBITORS OF GLUCOSE TRANSPORTERS (GLUTS)
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The present invention relates to 2,6-methanobenzo[g][1]oxacin-4-onecompounds and their analog compounds and pharmaceutically acceptable salts thereof as selective inhibitor of glucose transporters 1 and 3 (GLUTs 1 and 3), to methods of preparing said compounds, and to the use thereof as pharmaceutically active agents, especially for the prophylaxis and/or treatment of metabolic diseases, immunological diseases, autoimmune diseases, inflammation, graft versus host disease, cancer, and metastasis thereof. Furthermore, the present invention is directed to pharmaceutical composition comprising at least one of 2,6-methanobenzo[g][1]oxacin-4-one compounds and their analog compounds.
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- N-Boc-aminals as easily accessible precursors for less accessible N-Boc-imines: Facile synthesis of optically active propargylamine derivatives using Mannich-type reactions
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We developed a facile and practical synthesis of N-Boc-aminals, which can be used as precursors for less accessible N-Boc-imines. Aminals were obtained via simple dehydration condensation reactions of t-butyl carbamate (BocNH2) and various aldehydes in acetic anhydride, followed by filtration and washing with hexane. The obtained N-Boc-alkynylaminals could be successfully applied in enantioselective Mannich-type reactions, catalyzed by chiral phosphoric acids, to afford optically active propargylamine derivatives.
- Yurino, Taiga,Aota, Yusuke,Asakawa, Daisuke,Kano, Taichi,Maruoka, Keiji
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p. 3687 - 3700
(2016/06/06)
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- Direct Asymmetric Friedel-Crafts Reaction of Naphthols with Acetals Catalyzed by Chiral Bronsted Acids
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The Friedel-Crafts method synthesis of chiral ethers from various acetals and naphthols catalyzed by chiral Bronsted acids with acetic acid as an effective additive is described. We found that the chiral phosphoric acid (R)-TRIP could efficiently catalyze the asymmetric Friedel-Crafts reaction of naphthols with acetals affording chiral ethers in good enantioselectivity and yield.
- Qin, Long,Wang, Pei,Zhang, Yixin,Ren, Zhengxiang,Zhang, Xin,Da, Chao-Shan
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p. 571 - 574
(2016/03/01)
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- Bronsted acid-catalyzed, highly enantioselective addition of enamides to in situ-generated ortho-quinone methides: A domino approach to complex acetamidotetrahydroxanthenes
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The highly enantioselective conjugate addition of enamides and enecarbamates to in situ-generated ortho-quinone methides, upon subsequent N,O-acetalization, gives rise to acetamido-substituted tetrahydroxanthenes with generally excellent enantio- and dias
- Saha, Satyajit,Schneider, Christoph
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p. 2348 - 2352
(2015/02/05)
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- Synthesis of novel chiral phosphoric acid-bearing two acidic phenolic hydroxyl groups and its catalytic evaluation for enantioselective Friedel-Crafts alkylation of indoles and enones
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A novel chiral phosphoric acid catalyst bearing two acidic phenolic hydroxyl groups was synthesized. Its catalytic activity as a chiral Br?sted acid has been examined in the enantioselective Friedel-Crafts alkylation of indoles and enones as a model reaction. In comparison with the other chiral phosphoric acid catalysts, the reaction catalyzed by the novel chiral catalyst afforded the desired 3-substituted indoles in a higher enantioselectivity (up to 69% ee).
- Liu, Xiong-Li,Yu, Zhang-Biao,Pan, Bo-Wen,Chen, Lin,Feng, Ting-Ting,Zhou, Ying
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p. 628 - 634
(2015/03/30)
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- Enantioselective organocatalytic fluorination-induced Wagner-Meerwein rearrangement
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Cracked under strain: Strained allylic cyclobutanols and cyclopropanols readily undergo a ring expansion described by the title rearrangement. This reaction is promoted by catalytic amounts of 1 and displays high tolerance with respect to the substrate scope. The corresponding β-fluoro spiroketone products are isolated in high yields and with excellent stereoselectivities. EDG=electron-donating group, EWG=electron-withdrawing group. Copyright
- Romanov-Michailidis, Fedor,Guénée, Laure,Alexakis, Alexandre
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supporting information
p. 9266 - 9270
(2013/09/12)
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- Chiral phosphoric acid catalyzed asymmetric friedel-crafts alkylation of indoles with nitroolefins
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Asymmetric Michael-type Friedel-Crafts (F-C) alkylations of indoles with nitroolefins catalyzed by a chiral H8-BINOL-based phosphoric acid were investigated. The reactions took place very smoothly in the presence of only 5 mol-% of catalyst at
- Tang, Hong-Ying,Zhang, Zhong-Biao
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p. 2038 - 2046
(2011/11/30)
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- A protecting-group-free route to chiral BINOL-phosphoric acids
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A two-step, protecting group-free route for the synthesis of 3,3′-disubstituted and 6,6′-disubstituted chiral BINOL-phosphoric acids has been realized starting from commercially available brominated BINOLs. This synthesis relies on the direct Suzuki coupl
- Li, Baojian,Chiu, Pauline
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p. 3932 - 3937
(2011/09/14)
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- RETRACTED ARTICLE: Enantioselective organocatalytic hantzsch synthesis of polyhydroquinolines
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The four-component Hantzsch reaction provides access to pharmaceutically important dihydropyridines. To expand the utility of this method, we have developed a route under organocatalytic conditions with good yields and excellent ee's. Through catalyst scr
- Evans, Christopher G.,Gestwicki, Jason E.
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supporting information; experimental part
p. 2957 - 2959
(2009/12/05)
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- Facile and efficient enantioselective strecker reaction of ketimines by chiral sodium phosphate
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A facile and efficient enantioselective Strecker reaction of ketimines catalyzed by a chiral alkali-metal salt has been developed. When 10 mol% BNPNa (BNP=1,1'-binaphthyl-2,2'-diylphosphate) prepared in situ and 10 mol% para-tert-butylortho-adamantylphenol (PBAP) were introduced into the reaction, up to 96% yield and up to 95% ee (ee=enantiomeric excess) were obtained. Both aliphatic and aromatic ketimines, especially sterically bulky cyclic ketimines derived from β-acetonaphthone, α-indanone, and α-tetralone were found suitable for this reaction. On the basis of the experimental results and previous reports, trimethylsilyl cyanide (TMSCN) was indicated to be the real reactive nucleophile despite the existence of PBAP, and a possible working model was proposed to explain the origin of the asymmetric induction. The facile availability of 1,1'-binaphthyl-2,2'-diylphosphoric acid (BNPH) and the simplicity of the procedure are beneficial for practical applications.
- Shen, Ke,Liu, Xiaohua,Cai, Yunfei,Lin, Lili,Feng, Xiaoming
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supporting information; scheme or table
p. 6008 - 6014
(2010/02/28)
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- Chiral phosphoric acid catalyzed asymmetric Friedel-Crafts alkylation of indoles with simple α,β-unsaturated aromatic ketones
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Asymmetric Michael-type Friedel-Crafts (F-C) alkylations of indoles with nonchelating α,β-unsaturated aromatic ketones catalyzed by a chiral H8-BINOL-based phosphoric acid were investigated. The reactions took place smoothly in the presence of
- Tang, Hong-Ying,Lu, Ai-Dang,Zhou, Zheng-Hong,Zhao, Guo-Feng,He, Lian-Nian,Tang, Chu-Chi
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experimental part
p. 1406 - 1410
(2009/04/04)
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- Chiral lithium salts of phosphoric acids as Lewis acid-base conjugate catalysts for the enantioselective cyanosilylation of ketones
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The catalytic enantioselective cyanosilylation of aromatic ketones was developed by using chiral lithium salts of (R)-BINOL- or (S)-BINAM-derived phosphoric acid compounds. In the presence of 10 mol% of chiral conjugate lithium salts, the corresponding tertiary cyanohydrins were obtained in high yields with moderate to high enantio-selectivities. This is the first efficient example of asymmetric catalysis using lithium salts of synthetically useful chiral phosphoric acid compounds. A possible catalytic mechanism and transition states are also discussed as a preliminary working hypothesis.
- Hatano, Manabu,Ikeno, Takumi,Matsumura, Tokihiko,Torii, Shinobu,Ishihara, Kazuaki
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supporting information; experimental part
p. 1776 - 1780
(2009/07/01)
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- Chiral Bronsted acid catalyzed enantioselective Mannich-type reaction
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Mannich-type reaction of ketene silyl acetals with aldimines proceeded catalytically by means of a phosphoric acid diester, derived from (R)-BINOL, as a chiral Bronsted acid to afford β-amino esters with good diastereoselectivity in favor of the syn isomer and high enantioselectivity (up to 96% ee). The highest enantioselectivity was achieved by the phosphoric acid diester bearing 4-nitrophenyl groups on the 3,3′-positions of BINOL. The N-2-hydroxyphenyl group of aldimine was found to be essential for the present Mannich-type reaction. In combination with these experimental investigations, two possible monocoordination and dicoordination pathways were explored using density functional theory calculations (BHandHLYP/6-31G*). The present reaction proceeds via a dicoordination pathway through the zwitterionic and nine-membered cyclic transition state (TS) consisting of the aldimine and the phosphoric acid. The re-facial selectivity was also well-rationalized theoretically. The nine-membered cyclic structure and aromatic stacking interaction between the 4-nitrophenyl group and N-aryl group would fix the geometry of aldimine on the transition state, and the si-facial attacking TS is less favored by the steric hindrance of the 3,3′-aryl substituents.
- Yamanaka, Masahiro,Itoh, Junji,Fuchibe, Kohei,Akiyama, Takahiko
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p. 6756 - 6764
(2008/02/06)
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- ASYMMETRIC-SYNTHESIS CATALYST BASED ON CHIRAL BROENSTED ACID AND METHOD OF ASYMMETRIC SYNTHESIS WITH THE CATALYST
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A compound usable as an asymmetric synthesis catalyst which can be easily synthesized without using any metal such as a lanthanoid group element; a method of asymmetric synthesis with the compound; and a chiral compound obtained by the asymmetric synthesis method. A Broensted acid is used as a catalyst in asymmetric synthesis, the chiral Broensted acid being represented by formula (1) below or formula (3) below. The asymmetric synthesis method employs the catalyst. Asymmetric synthesis with the catalyst gives a chiral compound.
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Page/Page column 15
(2010/11/08)
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