- Cu(I)/Chiral Bisoxazoline-Catalyzed Enantioselective Doyle-Kirmse Reaction of Allenyl Sulfides with α-Diazoesters
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Herein, a Cu(I)-catalyzed enantioselective Doyle-Kirmse reaction of allenyl sulfides and α-diazoesters is reported, which provides an efficient synthetic route to enantio-enriched chiral tertiary homopropargylic sulfides. This reaction features high enantioselectivities (up to 96 % ee) and good functional group tolerance. The alkyl substituted α-diazoester has also been demonstrated as the efficient substrates in the asymmetric Doyle-Kirmse reaction. Mechanistic studies, including kinetic experiments, were conducted to gain insights into the details of the reaction pathway. The potential synthetic utility of this protocol has also been demonstrated.
- Li, Shu-Sen,Wang, Jianbo,Wang, Kang
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supporting information
(2022/03/17)
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- Ru(ii)-Pheox-catalyzed Si-H insertion reaction: construction of enantioenriched carbon and silicon centers
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We established a highly enantioselective Si-H insertion reaction to construct chiral centers at the carbon and silicon atoms, using a Ru(ii)-pheox catalyst. The catalytic asymmetric Si-H insertion reaction of α-methyl-α-diazoesters proceeded smoothly with excellent stereoinduction at both the neighboring carbon and silicon atoms (up to 99% yield and 99% ee).
- Nakagawa, Yoko,Chanthamath, Soda,Fujisawa, Ikuhide,Shibatomi, Kazutaka,Iwasa, Seiji
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supporting information
p. 3753 - 3756
(2017/04/03)
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- Highly enantioselective catalytic 1,3-dipolar cycloadditions of α-alkyl diazoacetates: Efficient synthesis of functionalized 2-pyrazolines
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Highly enantioselective 1,3-dipolar cycloaddition reactions of α-substituted diazoacetates are accomplished by catalysis of the chiral oxazaborolidinium ion. Functionalized 2-pyrazolines are synthesized in high to excellent enantiomeric ratios (up to >99:
- Lee, Sung Il,Kim, Ka Eun,Hwang, Geum-Sook,Ryu, Do Hyun
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supporting information
p. 2745 - 2749
(2015/04/22)
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- Williamson Ether Synthesis with Phenols at a Tertiary Stereogenic Carbon: Formal Enantioselective Phenoxylation of β-Keto Esters
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The enantioselective formation of α-aryloxy-β-keto esters is described for the first time. Lewis acid catalyzed enantioselective chlorination of β-keto esters and subsequent SN2 reactions with phenols yielded α-aryloxy-β-keto esters with up to 96 % ee. Favorskii rearrangement of α-chloro-β-keto esters was also found to give 1,2-diesters with slightly reduced enantiopurity.
- Shibatomi, Kazutaka,Kotozaki, Manato,Sasaki, Nozomi,Fujisawa, Ikuhide,Iwasa, Seiji
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supporting information
p. 14095 - 14098
(2015/09/28)
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- Catalytic enantioselective carbon insertion into the β-vinyl C-H bond of cyclic enones
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Chiral oxazaborolidinium ion-catalyzed Csp2-H functionalization of enones using diazoacetate has been developed. Various β-substituted cyclic enones were synthesized in high yield (up to 99%) with high to excellent enantioselectivity (up to 99%
- Lee, Sung Il,Hwang, Geum-Sook,Ryu, Do Hyun
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supporting information
p. 7126 - 7129
(2013/07/05)
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- Catalytic carbon insertion into the β-vinyl C-H bond of cyclic enones with alkyl diazoacetates
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The first example of the boron Lewis acid catalyzed Csp2-H functionalization of cyclic enones was achieved using diazoacetates. The insertion of the carbon atom of diazoacetates utilizes BF3? Et2O or a newly designed oxaza
- Lee, Sung Il,Kang, Byung Chul,Hwang, Geum-Sook,Ryu, Do Hyun
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supporting information
p. 1428 - 1431
(2013/06/26)
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- Substrate range of the titanium TADDOLate catalyzed asymmetric fluorination of activated carbonyl compounds
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The substrate range of the [TiCl2(TADDOLate)] (TADDOL=α,α,α′,α′-tetraaryl-1,3-dioxolane-4, 5-dimethanol)-catalyzed asymmetric α-fluorination of activated β-carbonyl compounds has been investigated. Optimal conditions for catalysis are characterized by using 5 mol-% of TiCl2(naphthalen-1- yl)-TADDOLate) as catalyst in a saturated (0.14 mol/l) MeCN solution of F-TEDA (1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis- [tetrafluoroborate]) at room temperature. A series of α-methylated β-keto esters (3-oxobutanoates, 3-oxopentanoates) with bulky benzyl ester groups (60-90% ee) or phenyl ester (67-88% ee) have been fluorinated readily, whereas α-acyl lactones were also readily fluorinated, but gave lower inductions (13-46% ee). Double stereochemical differentiation in β-keto esters with chiral ester groups raised the stereoselectivity to a diastereomeric ratio (dr) of up to 96.5:3.5. For the first time, β-keto S-thioesters were asymmetrically fluorinated (62-91.5% ee) and chlorinated (83% ee). Lower inductions were observed in fluorinations of 1,3-diketones (up to 40% ee) and β-keto amides (up to 59% ee). General strategies for preparing activated β-carbonyl compounds as important model substrates for asymmetric catalytic α-functionalizations are presented (>60 examples). Copyright
- Bertogg, Andreas,Hintermann, Lukas,Huber, Dominique P.,Perseghini, Mauro,Sanna, Maria,Togni, Antonio
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experimental part
p. 353 - 403
(2012/05/07)
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- Enantioselective carbenoid insertion into phenolic O-H bonds with a chiral copper(I) imidazoindolephosphine complex
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The enantioselective O-H carbenoid insertion reaction with a new chiral copper(I) imidazoindolephosphine complex has been developed. The chiral copper(I) complex catalyzed the insertion of carbenoids derived from α-diazopropionates into the O-H bonds of various phenol derivatives to give the corresponding α-aryloxypropionates with up to 91% ee.
- Osako, Takao,Panichakul, Duanghathai,Uozumi, Yasuhiro
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supporting information; experimental part
p. 194 - 197
(2012/02/16)
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- Highly enantioselective chlorination of β-keto esters and subsequent SN2 displacement of tertiary chlorides: A flexible method for the construction of quaternary stereogenic centers
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Highly enantioselective chlorination of β-oxo esters and subsequent stereospecific substitution of tertiary chlorides are described. Enantioselective chlorination of β-keto esters and malonates was performed using a chiral Lewis acid catalyst prepared from Cu(OTf)2 and the newly developed spirooxazoline ligand 2 to yield the desired α-chlorinated products with high enantioselectivity (up to 98% ee). Nucleophilic substitution of the resulting chlorides proceeded smoothly to afford a variety of chiral molecules such as α-amino, α-alkylthio, and α-fluoro esters, without loss of enantiopurity. The results of X-ray crystallographic analysis proved that Walden inversion occurs at the chlorinated tertiary carbon center. These results supported the fact that the substitution proceeds via an S N2 mechanism.
- Shibatomi, Kazutaka,Soga, Yoshinori,Narayama, Akira,Fujisawa, Ikuhide,Iwasa, Seiji
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supporting information; body text
p. 9836 - 9839
(2012/07/30)
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- COMPOUNDS AND COMPOSITIONS AS MODULATORS OF GPR119 ACTIVITY
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The invention provides compounds, pharmaceutical compositions comprising such compounds and methods of using such compounds to treat or prevent diseases or disorders associated with the activity of GPR119.
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Page/Page column 169-170
(2011/02/24)
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- Novel chiral pyrrolidinone scaffolds derived from threonine with antibacterial activity
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The synthesis of chiral pyrrolidinones derived from threonine, making use of a Dieckmann or aldol ring closure, is described. Compounds were found to exhibit antibacterial activity, for which the correlation with various physiochemical parameters was examined. This chiral tetramate scaffold may provide a useful template for fragment-based drug design providing rapid access to novel antibacterial compound libraries.
- Anwar, Muhammad,Cowley, Andrew R.,Moloney, Mark G.
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experimental part
p. 1758 - 1770
(2010/10/18)
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- Ethynyl-1,2-benziodoxol-3(1H)-one (EBX): An exceptional reagent for the ethynylation of keto, cyano, and nitro esters
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Hot alkyne! The in situ generation of ethynyl-1,2-benziodoxol-3(1H)-one (EBX) from a silyl-protected reagent by using TBAF is reported. EBX displayed exceptional acetylene transfer ability onto stabilized enolates (see scheme), even at -78 □°C. The mild reaction conditions allowed the first ethynylation reactions of linear keto, cyano, and nitro esters in high yields to give all-carbon quaternary centers or non-natural amino acids after selective reduction of the nitro group.
- Gonzalez, Davinia Fernandez,Brand, Jonathan P.,Waser, Jerome
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supporting information; experimental part
p. 9457 - 9461
(2010/10/03)
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- Synthesis of (Z)-Trisubstituted olefins by decarboxylative Grob-Type fragmentations: Epothilone D, discodermolide, and peloruside A
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Methyl-branched (Z)-trisubstituted olefins are found in many polyketides with interesting biological activity, such as epothilone D (1), discodermolide (3), and peloruside A (2). Despite the employment of numerous different strategies, this motif has often been the weak point in total synthesis. Thus, we present a novel hydroxideinduced Grob-type fragmentation as an easy access to trisubstituted olefins. In our case, β-mesyloxy δ-lactones with three stereogenic centers were chosen whose fragmentation underlies a high stereoelectronic control. Major challenges in the syntheses were the instailation of quaternary stereocenters, achieved by enzymatic desymmetrization of meso-diesters and by aluminiumpromoted stereoselective rearrangement of chiral epoxides, respectively. Different aldol strategies were developed for the formation of the fragmentation precursors. Additionally a short survey about nucleophilic additions to aldehydes with quaternary α-centers is presented.
- Prantz, Kathrin,Mulzer, Johann
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supporting information; experimental part
p. 485 - 506
(2010/06/14)
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- Stereoselective construction of seven-membered rings with an all-carbon quaternary center by direct tiffeneau-demjanov-type ring expansion
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Insertion of one methylene unit into the C-C bond of cyclohexanones is apotentially useful, straightforward method for the construction of seve n-membered carbocycles. An especially appealing but largely unexplored method in this arena is the nucleophilic
- Hashimoto, Takuya,Naganawa, Yuki,Maruoka, Keiji
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supporting information; experimental part
p. 6614 - 6617
(2009/09/26)
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- Catalytic Michael reactions of ketoesters with a camphor-derived acrylate equivalent: Stereoselective access to all-carbon quaternary centers
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(Chemical Equation Presented) A camphor-based α′-hydroxy enone reagent acts as a chiral acrylate equivalent in copper-catalyzed Michael reactions of β-keto esters and affords products that possess all-carbon quaternary stereocenters of high enantiomeric purity.
- Palomo, Claudio,Oiarbide, Mikel,Garcia, Jesus M.,Banuelos, Patricia,Odriozola, Jose M.,Razkin, Jesus,Linden, Anthony
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supporting information; experimental part
p. 2637 - 2640
(2009/05/27)
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- Hexamethylenetetramine-mediated transesterification of β-keto esters
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Treatment of methyl or ethyl β-keto esters with primary, secondary, or tertiary alcohols in the presence of a catalytic amount of hexamethylenetetramine results in good to high yields of the corresponding esters. Georg Thieme Verlag Stuttgart.
- Ribeiro, Rodrigo S.,De Souza, Rodrigo O. M. A.,Vasconcellos, Mario L. A. A.,Oliveira, Bianca L.,Ferreira, Leonardo C.,Aguiar, Lucia C. S.
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- MODULATORS OF GLUCOCORTICOID RECEPTOR, AP-1, AND/OR NF-kB ACTIVITY AND USE THEREOF
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Non-steroidal compounds are provided which are useful in treating diseases associated with modulation of the glucocorticoid receptor, AP-1, and/or NF-?B activity including obesity, diabetes, inflammatory and immune diseases, and have the structure of formula (I) or an enantiomer, a diastereomer, a pharmaceutically acceptable salt, or hydrate thereof, where J is selected from NR1 or C(R4)(R4a); K is selected from NR2 or C(R5)(R5a); L is selected from NR3 or C(R6)(R6a); and A, X, Y, R1, R2, R3, R4, R4a, R5, R5a, R6, R6a, R8, R10, R11, and n are defined herein. Also provided are pharmaceutical compositions and methods of treating obesity, diabetes and inflammatory or immune associated diseases comprising said compounds.
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Page/Page column 98
(2010/11/25)
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- A Novel Concept of Acid Proliferation. Autocatalytic Fragmentation of an Acetoacetate Derivative as an Acid Amplifier
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tert-Butyl 2-methyl-2-(p-toluenesulfonyloxymethyl)acetoacetate was designed to be subjected to the acid-catalyzed fragmentation to liberate p-toluenesulfonic acid which can act as the autocatalyst to lead to the increment of the acid concentration in geometric progression.
- Ichimura, Kunihiro,Arimitsu, Koji,Kudo, Kazuaki
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p. 551 - 552
(2007/10/03)
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- Diastereomeric 5,6-Dimethyl-4H-1,3-dioxin-4-ones from (-)-(1R,4S)-Menthone: Synthesis and NMR Analysis
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The two diastereomers of spirocyclic 5,6-dimethyl-4H-1,3-dioxin-4-one (5,6) have been synthesized by acetalization of tert-butyl 2-methyl-3-oxobutanoate (2) with (-)-menthone (4).Their structures have been determined by NMR analysis.
- Jansen, Ursula,Runsink, Jan,Mattay, Jochen
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p. 283 - 285
(2007/10/02)
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- New Fluorinating Reagents. Part II. Preparation and Synthetic Application of a Saccharin Derived N-Fluorosultam
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The synthesis of the new saccharin derived N-fluorosultam 1 is described.A comparative study with commercially available N-fluorosulfonamides shows 1 to be a superior fluorinating reagent for the synthesis of α-fluorocarbonyl compounds.
- Differding, Edmond,Lang, Robert W.
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p. 1248 - 1252
(2007/10/02)
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- Stereochemical Control in Microbial Reduction. 9. Diastereoselective Reduction of 2-Alkyl-3-oxobutanoate with Bakers' Yeast
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Bakers' yeast reduces esters of 2-alkyl-3-oxobutanoic acid (CH3COCHRCO2R'; R=methyl, ethyl, propyl, propargyl, and allyl) into the corresponding (S)-hydroxy esters with exclusive stereoselectivity, while the configuration at the 2-position of the hydroxy esters is either S (anti) or R (syn) depending on the structure of the alkoxyl group in the carboalkoxyl moeity of the ester.Oftently, the stereoselectivity with respect to the 2-position is not satisfactory.In general, the reduction of t-butyl esters exerts predominancy in the products, whereas that of 1,1-dimethylpropyl esters exerts the syn predominancy.A marked difference between these two esters in diastereoselectivity is dicussed from the view point of plausible conformations of the esters.
- Nakamura, Kaoru,Miyai, Takehiko,Nagar, Ashish,Oka, Shinzaburo,Ohno, Atsuyoshi
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p. 1179 - 1187
(2007/10/02)
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- Synthesis of 1,3-dioxin-4-one Derivatives
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A facile and general synthesis of 2,2-dimethyl-1,3-dioxin-4-one derivatives (1) is reported.Treatment of β-keto acids with a mixture of isopropenyl acetate and conc. sulfuric acid gave 2,2-dimethyl-1,3-dioxin-4-ones (1).Similar treatment of tert-butyl esters of β-keto acids also gave 1.KEYWORDS - 2,2-dimethyl-1,3-dioxin-4-one derivative; diketene-acetone adduct; diketene; acylketene; β-keto acid; β-keto ester
- Sato, Masayuki,Ogasawara, Hiromichi,Oi, Keiichi,Kato, Tetsuzo
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p. 1896 - 1901
(2007/10/02)
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- Biosynthesis of Austdiol and Synthesis of a Deuterium Labelled Biogenetic Precursor
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Incorporation studies on austdiol (1), a metabolite from Aspergillus ustus were carried out with -acetate, -, and -methionine.Specific incorporation of 4,6-dihydroxy-3,5-dimethyl-2-(2-oxopropyl)benzaldehyde (2) into austdio
- Colombo, Lino,Gennari, Cesare,Poli, Giovanni,Scolastico, Carlo,Aragozzini, Fabrizio,Merendi, Cosetta
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p. 2745 - 2749
(2007/10/02)
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- Sudies on the Nactins: Total Synthesis of (+/-)-tert-Butyl 8-O-(tert-Butyldimethylsilyl)nonactate
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The title nonactic acid derivative (32) was prepared in racemic form from 2,3,5-tri-O-acetyl-γ-D-ribonolactone (17).Lactone 17 reacted with DBU to give 3-acetoxy-5-methylene-2,5-dihydrofuran-2-one (18), which on hydrogenation over Pd/CaCO3 stereoselective
- Barrett, Anthony G. M.,Sheth, Hiten G.
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p. 5017 - 5022
(2007/10/02)
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