- A 3D Organically Synthesized Porous Carbon Material for Lithium-Ion Batteries
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We report the first organically synthesized sp–sp3 hybridized porous carbon, OSPC-1. This new carbon shows electron conductivity, high porosity, the highest uptake of lithium ions of any carbon material to-date, and the ability to inhibit dange
- Zhao, Ziqiang,Das, Saikat,Xing, Guolong,Fayon, Pierre,Heasman, Patrick,Jay, Michael,Bailey, Steven,Lambert, Colin,Yamada, Hiroki,Wakihara, Toru,Trewin, Abbie,Ben, Teng,Qiu, Shilun,Valtchev, Valentin
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- Catalytic Enantioselective Dehydrogenative Si-O Coupling to Access Chiroptical Silicon-Stereogenic Siloxanes and Alkoxysilanes
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A rhodium-catalyzed enantioselective construction of triorgano-substituted silicon-stereogenic siloxanes and alkoxysilanes is developed. This process undergoes a direct intermolecular dehydrogenative Si-O coupling between dihydrosilanes with silanols or alocohols, giving access to a variety of highly functionalized chiral siloxanes and alkoxysilanes in decent yields with excellent stereocontrol, that significantly expand the chemical space of the silicon-centered chiral molecules. Further utility of this process was illustrated by the construction of CPL-active (circularly polarized luminescence) silicon-stereogenic alkoxysilane small organic molecules. Optically pure bis-alkoxysilane containing two silicon-stereogenic centers and three pyrene groups displayed a remarkable glum value with a high fluorescence quantum efficiency (glum = 0.011, φF = 0.55), which could have great potential application prospects in chiral organic optoelectronic materials.
- Zhu, Jiefeng,Chen, Shuyou,He, Chuan
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supporting information
p. 5301 - 5307
(2021/05/04)
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- Silicon-center chiral silicon-oxygen compound and preparation method thereof
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The invention belongs to the field of chiral silicon synthesis, and discloses a silicon-center chiral silicon-oxygen compound. The compound has a structure represented by general formula I shown in the specification. In the formula I, X is Si(R)n or a formula also shown in the specification, R is selected from alkyl, cycloalkyl and aryl, R is selected from alkyl, substituted phenyl and aryl, R is selected from alkyl, phenyl and substituted phenyl, n is 3, the three R are the same or different, R is selected from hydrogen and (C1-C4) alkyl, m is selected from 0, 1, 2 and 3, and Y is selected from substituted phenyl, substituted pyrenyl, aryl, heteroaryl and cycloalkyl. The invention also discloses a preparation method of the compound. Various highly functionalized chiral siloxanes and silyl ethers are obtained with good chemical, regional and stereo control and high yield, the variety of silicon center chiral compounds is expanded, and the method has the advantages of high enantioselectivity, wide substrate application range, mild reaction conditions, atom economy and the like. In addition, the compound provided by the invention has a huge application prospect in chiral organic photoelectric materials.
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Paragraph 0106; 0117-0118
(2021/07/24)
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- NOVEL STING AGONISTS
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The present invention provides compounds of Formula I′: wherein , W, X, Y, Z, Z1, Z2, R1, R2, R3, R4 and R5 are as defined herein, or a stereoisomer, tautomer, pharmaceutically acceptable salt, prodrug ester or solvate form thereof, wherein all of the variables are as defined herein. These compounds are effective at modulating the STING protein and thus can be used as medicaments for treating or preventing disorders affected by the agonism of STING.
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Paragraph 0795; 0799; 0801
(2020/05/14)
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- Highly Selective Hydroxylation and Alkoxylation of Silanes: One-Pot Silane Oxidation and Reduction of Aldehydes/Ketones
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An efficient chemoselective iridium-catalyzed method for the hydroxylation and alkoxylation of organosilanes to generate hydrogen gas and silanols or silyl ethers was developed. A variety of sterically hindered silanes with alkyl, aryl, and ether groups were tolerated. Furthermore, this atom-economical catalytic protocol can be used for the synthesis of silanediols and silanetriols. A one-pot silane oxidation and chemoselective reduction of aldehydes/ketones was also realized.
- Luo, Nianhua,Liao, Jianhua,Ouyang, Lu,Wen, Huiling,Zhong, Yuhong,Liu, Jitian,Tang, Weiping,Luo, Renshi
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p. 165 - 171
(2020/01/21)
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- Metal-free visible-light-mediated aerobic oxidation of silanes to silanols
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Oxidation of silanes into silanols using water/air has attracted considerable attention. The known methods with no exception required a metal catalyst. Herein we report the first metal-free method: 2 mol% Rose Bengal as the catalyst, air (O2) as the oxidant, water as the additive and under visible light irradiation. While this method produces various silanols in a simple, cost-effective, efficient (92%–99% yields) and scalable fashion, its reaction mechanism is very different than the reported ones associated with metal catalysis.
- Wang, Jing,Li, Bin,Liu, Li-Chuan,Jiang, Chenran,He, Tao,He, Wei
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p. 1594 - 1599
(2018/08/22)
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- O2-enhanced catalytic activity of gold nanoparticles in selective oxidation of hydrosilanes to silanols
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O2 acts as a nonconsumed activator for gold nanoparticles (AuNPs) in the oxidation of hydrosilanes to silanols with water under O2 atmosphere, providing an acceleration of more than 200 times relative to the reaction rate under Ar atmosphere. The AuNP catalyst under aerobic conditions exhibits high activity in the oxidation with high turnover numbers (1230000). Various hydrosilanes including less-reactive bulky ones can be converted to the corresponding silanols in excellent yields. Moreover, the present AuNP catalyst is reusable while maintaining the high performance.
- Urayama, Teppei,Mitsudome, Takato,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 1062 - 1064
(2015/09/02)
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- Nonhydrolytic synthesis of silanols by the hydrogenolysis of benzyloxysilanes
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The hydrogenolysis of benzyloxysilanes was smoothly catalyzed by Pd/C in THF to give corresponding silanols under nonhydrolytic conditions. The reaction proved to be applicable to various benzyloxysilanes giving silanemonools, diol, and triol.
- Igarashi, Masayasu,Matsumoto, Tomohiro,Sato, Kazuhiko,Ando, Wataru,Shimada, Shigeru
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supporting information
p. 429 - 431
(2014/04/17)
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- Stereocontrolled synthesis of syn-β-hydroxy-α-amino acids by direct aldolization of pseudoephenamine glycinamide
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β-Hydroxy-α-amino acids figure prominently as chiral building blocks in chemical synthesis and serve as precursors to numerous important medicines. Reported herein is a method for the synthesis of β-hydroxy- α-amino acid derivatives by aldolization of pseudoephenamine glycinamide, which can be prepared from pseudoephenamine in a one-flask protocol. Enolization of (R,R)- or (S,S)-pseudoephenamine glycinamide with lithium hexamethyldisilazide in the presence of LiCl followed by addition of an aldehyde or ketone substrate affords aldol addition products that are stereochemically homologous with L- or D-threonine, respectively. These products, which are typically solids, can be obtained in stereoisomerically pure form in yields of 55-98 %, and are readily transformed into β-hydroxy-α-amino acids by mild hydrolysis or into 2-amino-1,3-diols by reduction with sodium borohydride. This new chemistry greatly facilitates the construction of novel antibiotics of several different classes. On aldol: Enolization of (R,R)- or (S,S)-pseudoephenamine glycinamide with lithium hexamethyldisilazide (LiHMDS) in the presence of LiCl followed by addition of either an aldehyde or ketone substrate affords aldol addition products which are stereochemically homologous with L- or D-threonine, respectively. These products can be obtained in stereoisomerically pure form in yields of 55-98 %, and are readily transformed into β-hydroxy-α-amino acids by mild hydrolysis or into 2-amino-1,3-diols by reduction.
- Seiple, Ian B.,Mercer, Jaron A. M.,Sussman, Robin J.,Zhang, Ziyang,Myers, Andrew G.
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supporting information
p. 4642 - 4647
(2014/05/20)
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- Synthesis of formylsilanes through oxidative cleavage of α-silyl glycols
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A convenient method for the synthesis and isolation of highly reactive formylsilanes by oxidative cleavage of α-silyl glycols is presented. The mild conditions provide an entry to acid- and heat-sensitive members of this theoretically intriguing class of compounds. The utility of the method is demonstrated through the isolation and subsequent diastereoselective derivatization of t-BuMe2- and t-BuPh2-formylsilanes, previously not reported in isolated form.
- Von Wachenfeldt, Henrik,Strand, Daniel
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p. 12268 - 12273
(2014/01/06)
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- N-silyloxaziridines: Synthesis and use for electrophilic amination
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N-Silyloxaziridines were synthesized for the first time. Their tert-butyldiphenylsilyl (TBDPS) derivatives were stable reagents that were prepared on a multigram scale in three steps and in 44% overall yield from the corresponding benzylamines. They were mild electrophilic aminating reagents that reacted at room temperature with diversely substituted primary and secondary amines to produce N-monoalkyl or N,N-dialkyl benzaldehyde hydrazones in 44a-87% yield.
- Richy, Nicolas,Ghoraf, Mohammed,Vidal, Jo?lle
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p. 10972 - 10977
(2013/02/22)
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- A Lewis acid-promoted reduction of acylsilanes to α-hydroxysilanes by diethylzinc
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We report here the first example of the reduction of acylsilanes to α-hydroxysilanes, in which diethylzinc was used as a highly reactive agent in the presence of Ti(OiPr)4 or other Lewis acids. The reduction typically proceeds to give synthetically useful α-hydroxysilanes in good yields.
- Gao, Guang,Bai, Xing-Feng,Li, Fei,Zheng, Long-Sheng,Zheng, Zhan-Jiang,Lai, Guo-Qiao,Jiang, Kezhi,Li, Fuwei,Xu, Li-Wen
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supporting information; scheme or table
p. 2164 - 2166
(2012/05/05)
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- Primary alkyl bromides from dimethylthiocarbamates
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The conversion of primary alkyl dimethylthiocarbamates into alkyl bromides using the Vilsmeier reagent occurs in high yields in the presence of other non-acid sensitive and non-nucleophilic functional groups. Georg Thieme Verlag Stuttgart · New York.
- Moynihan, Meghan F.,Tucker, Joseph W.,Abelt, Christopher J.
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experimental part
p. 3565 - 3568
(2009/06/18)
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- Mechanistic study on the base-promoted reaction of allylphenylsilanes to alkenylsilanols
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On treatment of allylphenylsilanes with t-BuOK and 18-crown-6 in DMSO, isomerization of the olefinic double bond and subsequent substitution of the phenyl group with a hydroxy group took place smoothly to afford alkenylsilanol derivatives in good yields. The reaction mechanism was investigated using 18O-labeled sulfoxide. We found that a (methylsulfinyl)methyl anion generated from DMSO participated in this reaction.
- Imazeki, Shigeaki,Sugawara, Hiroo,Sano, Atsunori,Akiyama, Takahiko
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body text
p. 623 - 629
(2009/04/11)
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- Application of the B-alkyl Suzuki-Miyaura cross-coupling reaction to the stereoselective synthesis of analogues of (3S)-oxidosqualene
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(Chemical Equation Presented) A general method is described for the direct and stereoselective synthesis of epoxypolyenes via Suzuki-Miyaura cross-coupling reaction of 1-iodoalkenes with B-alkylboron compounds. It allows for the straightforward and conver
- Winne, Johan M.,Guang, Bing,D'Herde, Jo,De Clercq, Pierre J.
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p. 4815 - 4818
(2007/10/03)
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- Total synthesis of scytophycin C. 1. Stereoselective syntheses of the C(1)-C(18) segment and the C(19)-C(31) segment
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[Equation presented] Stereoselective total synthesis of scytophycin C, a marine 22-membered macrolide displaying potent activity against a variety of human carcinoma cell lines, has been reported in which the polypropionate structure bearing contiguous as
- Nakamura, Ryoichi,Tanino, Keiji,Miyashita, Masaaki
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p. 3579 - 3582
(2007/10/03)
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- Stereoselective tetrapyrido[2,1-a]isoindolone synthesis via carbanionic and radical intermediates: a model study for the Tacaman alkaloid D/E ring fusion.
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Cyclization under both radical and carbanionic conditions of N-substituted 3-phenylsulfanylisoindolin-1-one 14 containing a chiral N-tether incorporating an enoate ester as the acceptor leads to tetrahydropyrido[2,1-a]isoindolones stereoselectively. The m
- Hunter, Roger,Richards, Philip
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p. 2348 - 2356
(2007/10/03)
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- 15-ketal postaglandins for the treatment of glaucoma or ocular hypertension
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A method of treating glaucoma or ocular hypertension in a patient, which comprises administering to the patient a pharmaceutically effective amount of a compound of formula I:
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Page column 21
(2010/11/29)
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- (S)-3,7-Dimethyl-2-oxo-6-octene-1,3-diol: An aggregation pheromone of the Colorado potato beetle, Leptinotarsa decemlineata (Say)
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(S)-3,7-Dimethyl-2-oxo-6-octene-1,3-diol has been identified as a male-produced pheromone from the Colorado potato beetle. Its gross structure was deduced from its mass and NMR spectra plus synthesis from geraniol. The absolute configuration was determined to be (S) by syntheses of both enantiomers from (R)- and (S)-linalool, respectively.
- Oliver, James E,Dickens, Joseph C,Glass, Thomas E
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p. 2641 - 2643
(2007/10/03)
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- PhSeSiR3-catalyzed group transfer radical reactions
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A novel design for initiating radical-based chemistry in a catalytic fashion is described. The design of the concept is based on the phenylselenyl group transfer reaction from alkyl phenyl selenides by utilizing PhSeSiR3 (1) as a catalytic reagent. The reaction is initiated by the homolytic cleavage of -C-Se- bond of an alkyl phenyl selenide by the in situ generated alkylsilyl radical (R3Si), obtained by the mesolysis of PhSeSiR3](·)- (1(·)-). The oxidative dimerization of counteranion PhSe- to PhSeSePh functions as radical terminator. The generation of 1(·)- is achieved by the photoinduced electron transfer (PET) promoted reductive activation of 1 through a photosystem comprising of a visible-light (410 nm)-absorbing electron rich DMA as an electron donor and ascorbic acid as a co-oxidant (Figure 1). The optimum mole ratio between the catalyst 1 and alkyl phenyl selenides for successful reaction is established to be 1:10. The generality of the concept is demonstrated by carrying out variety of radical reactions such as cyclization (10, 15-18), intermolecular addition (25), and tandem annulations (32).
- Pandey, Ganesh,Rao,Nageshwar Rao
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p. 4309 - 4314
(2007/10/03)
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- Base promoted preparation of alkenylsilanols from allylsilanes
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On treatment of allyl-t-butyldiphenylsilane with t-BuOK and 18-Crown-6 in DMSO at room temperature, isomerization of the olefinic double bond and subsequent substitution of phenyl group with hydroxy group took place smoothly to afford alkenylsilanol derivatives in good yields.
- Akiyama, Takahiko,Imazeki, Shigeaki
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p. 1077 - 1078
(2007/10/03)
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- Aplyronine A, a potent antitumor substance of marine origin, aplyronines B and C, and artificial analogues: Total synthesis and structure-cytotoxicity relationships
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The enantioselective total synthesis of aplyronine A (1), a potent antitumor substance of marine origin, was achieved by a convergent approach. Three segments 4, 5, and 6, corresponding to the C5-C11, C21-C27, and C28-C34 portions of aplyronine A (1), were prepared using the Evans aldol reaction and the Sharpless epoxidation as key steps. The coupling reaction of 4 with iodide 7 followed by Julia olefination with sulfone 8 gave the C5-C20 segment 9, while the Julia coupling reaction between segments 5 and 6 provided the C21-C34 segment 10. Julia olefination between segments 9 and 10 and the subsequent four-carbon homologation reaction led to seco acid 83, which was converted into aplyronine A (1) by Yamaguchi lactonization followed by the introduction of two amino acids. The use of the [(3,4-dimethoxybenzyl)oxy]methyl group as a protecting group for the hydroxyl at C29 was crucial for this synthesis. The enantioselective synthesis of two natural congeners, aplyronines B (2) and C (3), was also carried out using the intermediates for the synthesis of 1, which determined the absolute stereostructures of 2 and 3 unambiguously. To study the structure-cytotoxicity relationships of aplyronines, artificial analogues of 1 were synthesized and their cytotoxicities were evaluated: the trimethylserine moiety, two hydroxyl groups, and the side chain portion in 1 turned out to be important in the potent cytotoxicity shown by 1. Biological studies with aplyronine A (1) showed that 1 inhibited polymerization of G-actin to F-actin and depolymerized F-actin to G-actin.
- Kigoshi, Hideo,Suenaga, Kiyotake,Mutou, Tsuyoshi,Ishigaki, Takeshi,Atsumi, Toshiyuki,Ishiwata, Hiroyuki,Sakakura, Akira,Ogawa, Takeshi,Ojika, Makoto,Yamada, Kiyoyuki
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p. 5326 - 5351
(2007/10/03)
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- A New Fluoridolyzable Anchoring Linkage for Orthogonal Solid-Phase Peptide Synthesis: Design, Preparation, and Application of the N-(3 or 4)--tert-butylphenylsilyl>phenyl Pentanedioic Acid Monoamide (Pbs) Handle
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The silicon-containing bifunctional handle 2,4,5-trichlorophenyl N-(3 or 4)--tert-butylphenylsilyl>phenyl pentanedioate monoamide (1) (Pbs) has been prepared and evaluated for use in a new mild approach to solid-phase peptide sy
- Mullen, Daniel G.,Barany, George
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p. 5240 - 5248
(2007/10/02)
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- Acyclic Stereoselection. 25. Stereoselective Synthesis of the C-1 to C-7 Moiety of Erythronolide A.
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A stereoselective synthesis of aldehyde ester 1, a synthon for the C-1 to C-7 section of erythronolide A, is reported.The synthesis begins with β,γ-unsaturated aldehyde 12, which is prepared from mesityl oxide as shown in eq 2.Aldehyde 12 reacts with the preformed lithium enolates of reagents 13 and 5 to give, in each case, a 15:1 mixture of two aldols (eq 3 and 4).Reduction of the major isomer 16 from the reaction of 5 with lithium aluminum hydride followed by periodate cleavage of the resulting vicinal diol provides β-hydroxy aldehyde 20.This material is protected as triethylsilyl derivative 21, which is treated with the lithium enolate of BHT O-benzyllactate (22c).The resulting 5:1 mixture of aldols is converted into acetonides 27c and 28c, which are separated by chromatography.The stereostructure of the major acetonide 27c was elucidated by single-crystal X-ray analysis (Figure 1).Lithium aluminum hydride reduction of 27c gives alcohol 29, which is converted into acetate 34.Ozonolysis of this material gives aldehyde 35, which is oxidized by pyridinium dichromate in DMF.Diazomethane esterification provides diester 36, which is methanolized to hydroxy ester 37.Swern oxidation of 35 provides racemic ester aldehyde 1.Enantiomerically homogeneous 1 is obtained in similar sequence, via the O-methylmandelates 39a and 39b.
- Heathcock, Clayton H.,Young, Steven D.,Hagen, James P.,Pilli, Ronaldo,Badertscher, Ulrich
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p. 2095 - 2105
(2007/10/02)
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- Oxidation products of arachidonic acid II. The synthesis of methyl 8R,9S,11R-trihydroxy-5Z,12E,14Z-eicosatrienoate
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A stereospecific total synthesis of the title compound, 37, starting from diacetone glucose (9), is described.Key intermediates in the synthesis are 3-deoxy-5,6-anhydro-1,2-O-isopropylidene-glucofuranose (15), obtained in 50percent yield fom 9, and methyl
- Just, George,Luthe, Corinne
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p. 1799 - 1805
(2007/10/02)
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