- Butane-2,3-diacetal-desymmetrized glycolic acid - A new building block for the stereoselective synthesis of enantiopure α-hydroxy acids
-
According to a chiral memory protocol, a chiral glycolic acid equivalent, the butane-2,3-diacetal-desymmetrized glycolate 2, is obtained from chiral 3-halopropane-1,2-diols 1. Compound 2 is a new and effective building block for the synthesis of mono- and
- Diez, Elena,Dixon, Darren J.,Ley, Steven V.
-
-
Read Online
- Glycerol conversion to high-value chemicals: The implication of unnatural α-amino acid syntheses using natural resources
-
Glycerol derivatives are an important class of compounds, which have great applications as basic structural building blocks in organic synthesis. O-Benzylglycerol was oxidised to produce a high-value compound in high yield using a NaOtBu-O2 system. Furthermore, the synthetic utility of the resulting product was demonstrated by its transformation into unnatural α-amino acids, thus showing the valorisation of glycerol biomass.
- Park, Yun Ji,Yang, Jung Woon
-
p. 2615 - 2620
(2019/06/03)
-
- Total Synthesis of (+)-Prunustatin A: Utility of Organotrifluoroborate-Mediated Prenylation and Shiina MNBA Esterification and Macrolactonization to Avoid a Competing Thorpe-Ingold Effect Accelerated Transesterification
-
A convergent total synthesis of (+)-prunustatin A is described through the assembly of two key fragments and a macrolactonization. Shiina MNBA couplings were used for the formation of each of the four ester bonds in the tetralactone ring, including the key macrocyclization which was essential to minimize competing Thorpe-Ingold accelerated transesterification. Other key steps included an organoboron-based prenylation using potassium prenyltrifluoroborate and a carbonyldiimidazole-mediated coupling to form the salicylamide.
- Chojnacka, Maja W.,Batey, Robert A.
-
p. 5671 - 5675
(2018/09/13)
-
- Solvent-induced chirality switching in the enantioseparation of regioisomeric hydroxyphenylpropionic acids via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol
-
The enantioseparation of three hydroxyphenylpropionic acid isomers via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol has been demonstrated. The racemates of all three acid isomers were successfully separated with high efficiency (0.56–0.84) after single crystallization. For 2-hydroxy-3-phenylpropionic acid 4, the configuration of the less-soluble salt was controlled by the crystallization solvent: the (R)-4 salt was crystallized from water, while 2-propanol afforded the (S)-4 salt. The chiral recognition mechanism of the three acids was discussed based on the crystal structures of the diastereomeric salts.
- Kodama, Koichi,Nagata, Jun,Kurozumi, Nobuhiro,Shitara, Hiroaki,Hirose, Takuji
-
p. 460 - 466
(2017/03/23)
-
- Asymmetric Assembly of All-Carbon Tertiary/Quaternary Nonadjacent Stereocenters through Organocatalytic Conjugate Addition of α-Cyanoacetates to a Methacrylate Equivalent
-
An efficient, highly diastereo- and enantioselective assembly of acyclic carbonyl fragments possessing nonadjacent all-carbon tertiary/quaternary stereoarrays is reported based on a Br?nsted base catalyzed Michael addition/α-protonation sequence involving α-cyanoacetates and 2,4-dimethyl-4-hydroxypenten-3-one as novel methacrylate equivalent.
- Iriarte, Igor,Vera, Silvia,Badiola, Eider,Mielgo, Antonia,Oiarbide, Mikel,García, Jesús M.,Odriozola, José M.,Palomo, Claudio
-
p. 13690 - 13696
(2016/09/13)
-
- NEW THIENOPYRIMIDINE DERIVATIVES, A PROCESS FOR THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
-
Compounds of formula (I): wherein R1, R2, R3, R4, R5, R6, R7, R12, X, A and n are as defined in the description.
- -
-
Page/Page column 47
(2015/07/15)
-
- Asymmetric transfer hydrogenation of α-azido acrylates
-
The asymmetric transfer hydrogenation of α-azido acrylates has been explored, a range of α-hydroxy esters are produced with good enantioselectivities (80-90% ee). The reaction was conducted in the wet HCO2H/NEt3 with Ru-TsDPEN A.
- Ji, Yang,Xue, Ping,Ma, Dan-Dan,Li, Xue-Qiang,Gu, Peiming,Li, Rui
-
p. 192 - 194
(2015/02/05)
-
- A chemoselective oxidation of monosubstituted ethylene glycol: Facile synthesis of optically active α-hydroxy acids
-
A mild and efficient method for the synthesis of optically active α-hydroxy acids through chemoselective oxidation of monosubstituted ethylene glycols using the TEMPO-NaOCl reagent system is described. It is evident from our studies that the solvent, pH and reaction temperature are very crucial for the success of this oxidation. The versatility of this method has been demonstrated with a variety of aliphatic, aromatic and carbohydrate substrates bearing various functional groups. the Partner Organisations 2014.
- Chinthapally, Kiran,Baskaran, Sundarababu
-
p. 4305 - 4309
(2014/06/23)
-
- Solid-phase synthesis of tetrahydropyridazinedione-constrained peptides
-
The design and solid-phase synthesis of tetrahydropyridazine-3,6-dione (Tpd) peptidomimetics derived from backbone-aminated peptides is reported. The described protocol features the synthesis of chiral α-hydrazino acids suitable for chemoselective incorporation into growing peptide chains. Acid-catalyzed cyclization to form the Tpd ring during cleavage affords the target peptidomimetics in good yield and purity. The scope of Tpd incorporation is demonstrated through the synthesis of constrained peptides featuring nucleophilic/electrophilic side chains and sterically encumbered α-substituted hydrazino acid residues. (Chemical Equation Presented).
- Kang, Chang Won,Ranatunga, Sujeewa,Sarnowski, Matthew P.,Del Valle, Juan R.
-
p. 5434 - 5437
(2015/02/19)
-
- Kinetic resolution of mandelate esters via stereoselective acylation catalyzed by lipase PS-30
-
By using lipase PS-30 as catalyst, the kinetic resolution of a series of racemic mandelate esters has been achieved via stereoselective acylation. The value of kinetic enantiomeric ratio (E) reached up to 197.5. Substituent effect is briefly discussed.
- Chen, Peiran,Yang, Wenhong
-
supporting information
p. 2290 - 2294
(2014/04/17)
-
- Design and synthesis of novel 2-pyridone peptidomimetic falcipain 2/3 inhibitors
-
The structure-based design, chemical synthesis and in vitro activity evaluation of various falcipain inhibitors derived from 2-pyridone are reported. These compounds contain a peptidomimetic binding determinant and a Michael acceptor terminal moiety capable of deactivating the cysteine protease active site.
- Verissimo, Edite,Berry, Neil,Gibbons, Peter,Cristiano, M. Lurdes S.,Rosenthal, Philip J.,Gut, Jiri,Ward, Stephen A.,O'Neill, Paul M.
-
scheme or table
p. 4210 - 4214
(2009/04/10)
-
- Solution-phase peptide synthesis; Synthesis of 'North-Western' and 'South Eastern' fragments of the antifungal cyclodepsipeptide petriellin A
-
The solution-phase synthesis of two highly modified peptides, a hexamer and a heptamer, that constitute the two halves of the antifungal cyclic depsipeptide, Petriellin A, is reported. CSIRO 2008.
- Aurelio, Luigi,Brownlee, Robert T. C.,Hughes, Andrew B.
-
p. 615 - 629
(2008/12/22)
-
- Catalytic, asymmetric inverse electron demand hetero diels-alder reactions of o-benzoquinone derivatives and ketene enolates
-
We present an array of [4+2] cycloaddition reactions between ketene enolates, catalytically derived from acid chlorides and cinchona alkaloid nucleophilic catalysts in the presence of stoichiometric base, and o-benzoquinone derivatives. These cycloadditio
- Paull, Daniel H.,Wolfer, Jamison,Grebinski, James W.,Weatherwax, Anthony,Lectka, Thomas
-
p. 240 - 246
(2008/02/09)
-
- Catalytic, enantioselective [4 + 2]-cycloadditions of ketene enolates and o-quinones: Efficient entry to chiral, α-oxygenated carboxylic acid derivatives
-
We report catalytic, enantioselective [4 + 2]-cycloadditions of o-quinones with ketene enolates (derived from readily available acid chlorides) using cinchona alkaloid derivatives as catalysts to produce products in high enantiomeric excess (ee) and good
- Bekele, Tefsit,Shah, Meha H.,Wolfer, Jamison,Abraham, Ciby J.,Weatherwax, Anthony,Lectka, Thomas
-
p. 1810 - 1811
(2007/10/03)
-
- Pyridone compounds as inhibitors of bacterial type III protien secreation systems
-
In accordance with the present invention, compounds that inhibit Type III protein section have been identified, and methods for their use provided. In one aspect of the invention, compounds useful in the inhibition of Type III protein section and/or in the treatment and prevention of bacterial infections, particularly Gram-negative bacterial infections, are provided. In another aspect of the invention, methods are provided for the inhibition of Type III protein secretion and/or the treatment and prevention of bacterial infections, particularly Gram-negative bacterial infections using the compounds of the invention.
- -
-
Page/Page column 9-10
(2010/02/14)
-
- Trifluoromethanesulonic acid catalyzed alkylation of arenes with methyl (2R)-glycidate
-
Methyl (R)-glycidate (= methyl (R)-oxiranecarboxylate; 2) in superacidic trifluoromethanesulfonic acid medium reacts with electron-rich arenes to give α-hydroxy-β-arylpropanoate derivatives 3a-3f with high stereospecificity. At the same time, the observed
- Linares-Palomino, Pablo J.,Prakash, G. K. Surya,Olah, George A.
-
p. 1221 - 1225
(2007/10/03)
-
- Synthesis and application of phosphinoferrocenylaminophosphine ligands for asymmetric catalysis
-
(Chemical Equation Presented) A new class of bidentate ligands utilizing a phosphine-aminophosphine structure has been prepared on a ferrocenylethyl backbone in a straightforward and scalable fashion from acetylferrocene. The unique property of the α-ferrocenyl carbonium ion that allows the replacement of a variety of "leaving groups" with retention of configuration greatly facilitates the synthesis, and a number of ligands have been prepared by varying the nitrogen and phosphorus substituents on the aminophosphine. These readily prepared phosphinoferrocenylaminophosphines, known as BoPhoz ligands, show surprising hydrolytic and air stability, with no degradation after 3 years open to the air. The rhodium complexes of these ligands show exceedingly high enantioselectivities (generally > 95% ee) and activities often in excess of 50 000 catalyst turnovers per hour for the asymmetric hydrogenation of a wide variety of dehydro-α-amino acid and itaconic acid derivatives. They also show high activity and good to excellent enantioselectivity for the hydrogenation of a number of α-ketoesters.
- Boaz, Neil W.,Mackenzie, Elaine B.,Debenham, Sheryl D.,Large, Shannon E.,Ponasik Jr., James A.
-
p. 1872 - 1880
(2007/10/03)
-
- Preparation of enantiopure butane-2,3-diacetals of glycolic acid and alkylation reactions leading to α-hydroxyacid and amide derivatives
-
The preparation of butane-2,3-diacetal protected glycolic acid and related systems is described together with highly selective alkylation reactions of (R,R) and (S,S) butanediacetal protected glycolic acid. These compounds are readily deprotected to give
- Ley, Steven V.,Diez, Elena,Dixon, Darren J.,Guy, Richard T.,Michel, Patrick,Nattrass, Gillian L.,Sheppard, Tom D.
-
p. 3608 - 3617
(2007/10/03)
-
- Characterization of an abeo-taxane: Brevifoliol and derivatives
-
Brevifoliol is a natural diterpene isolated from Taxus baccata Nutt. A series of brevifoliol 1 derivatives, 2-8 and 10, were prepared for characterization and semisynthesis purposes and included the introduction of acetyl, Troc, and TES groups at C-5 and C-13. Derivatives 16-20 of 5-acetylbrevifoliol 2 were obtained via esterification with cinnamic acid, with both 2S-(-)- and 2R-(+)-3-phenyllactic acid, and with N-benzoyl-(2′ R,3′S)-3′-phenylisoserine at C-13. Brevifoliol compounds 12, 13, and 15 with either 2S-(-)-phenyllactate moieties at C-5 and C-13 or an N-benzoyl-(2′R,3′S)-3′-phenylisoserinyl at C-13 were also prepared. An abeo-taxane structure for 1 was clearly defined from the 13C NMR analysis of the 5-acetyl-13-oxo derivative 8 and from the conversion of 1 into 10, a conformationally restrained compound having a C-13, C-15 oxygen bridge. The biological activity of each of these derivatives is being studied.
- Tremblay, Steve,Soucy, Chantal,Towers, Neil,Gunning, Philip J.,Breau, Livain
-
p. 838 - 845
(2007/10/03)
-
- The N-Acyloxyiminium Ion Aza-Prins Route to Octahydroindoles: Total Synthesis and Structural Confirmation of the Antithrombotic Marine Natural Product Oscillarin
-
The first enantiocontrolled total synthesis of the marine natural product oscillarin is described. The proposed structure and absolute configuration of oscillarin is thus confirmed, and a previously assigned structure of a subunit was shown to be incorrect. The X-ray structure of an oscillarin-thrombin complex was resolved at 2.0 A resolution, which validated its potent inhibitory activity against the enzyme with an IC50 = 28 nM. Methodology was developed for the synthesis of enantiopure octahydroindole-2-carboxylic acids with usable functionality at C-6. The method consists of the halocarbocyclization of N-acyloxyiminium ions containing an olefinic tether in the presence of fin tetrachloride or fin tetrabromide. This N-acyloxyiminium ion aza-Prins carbocyclization proved to be general for the construction of octahydroindole and perhydroquinoline 2-carboxylic acids. Mechanistic rationales are based on an antiperiplanar attack of the terminal alkene on the iminium ion, leading to an incipient secondary carbocation which is trapped by halide via an equatorial attack. X-ray crystal structures of products corroborate the expected stereochemistry.
- Hanessian, Stephen,Tremblay, Martin,Petersen, Jens F. W.
-
p. 6064 - 6071
(2007/10/03)
-
- Process research of (R)-cyclohexyl lactic acid and related building blocks: A comparative study
-
(S)-Cyclohexyl lactic acid is a component of the selective E-selectin inhibitor 2 ((S)-cHexLact-2-0-(3-Galβ(1→3)ddGlc-(4→1)αFuc). We describe the evaluation of various synthetic routes to this building block: (A) diazotation of phenylalanine followed by phenyl ring hydrogenation; (B) phenyl ring hydrogenation of phenyl alanine followed by diazotation; (C) acidic hydrolysis of the cyanohydrin derived from phenylacetaldehyde, enantiomeric resolution of the resulting, racemic phenyl lactic acid via diasteromeric salt formation and phenyl ring hydrogenation; (D) enantioselective dihydroxylation of a cinnamate ester, followed by hydrogenation of the benzylic hydroxy group and the aromatic nucleus; (E) enantioselective biocatalytic reduction of phenylpyruvic acid, followed by phenyl ring hydrogenation. The development of (2R)-2-0-(4-nitrophenyl)sulfonyl-cyclohexyl lactic acid p-bromobenzylester 21 as a buidling block with improved crystallinity and stability is also described.
- Storz, Thomas,Dittmar, Peter,Fauquex, Pierre Francois,Marschal, Philippe,Lottenbach, Willy Urs,Steiner, Heinz
-
p. 559 - 570
(2013/09/05)
-
- The asymmetric synthesis of β-aryl-α-hydroxy esters from β-aryl-α,β-dihydroxy esters
-
α,β-Dihydroxy-β-aryl esters obtained via Sharpless asymmetric dihydroxylation (AD) of substituted cinnamate esters are reduced by sequential reaction with trimethyl orthoacetate and acetyl bromide followed by catalytic hydrogenolysis in methanol to give enantiomerically enriched β-aryl-α-hydroxy esters.
- Lawrence, Nicholas J,Brown, Stephen
-
p. 613 - 619
(2007/10/03)
-
- A Practical Method for Optical Resolution of Racemic Alcohols or Esters via Lipase-Catalyzed Transformation and Sulfation
-
Optically active esters were conveniently obtained from the corrasponding racemic alcohols or esters by lipase-catalyzed transformation, followed by sulfation. Sulfation by sulfurtrioxide pyridine complex enabled facile isolation of optically active esters by extraction instead of laborious column chromatography. The method would be especially adventageous on a large scale.
- Yamano, Toru,Kikumoto, Fumio,Yamamoto, Shozo,Miwa, Katsuhiko,Kawada, Mitsuru,Ito, Tatsuya,Ikemoto, Tomomi,Tomimatsu, Kiminori,Mizuno, Yukio
-
p. 448 - 449
(2007/10/03)
-
- Ribosome-mediated incorporation of hydrazinophenylalanine into modified peptide and protein analogues
-
(S)-α-Hydrazinophenylalanyl-tRNA(Phe), an aminoacyl-tRNA derivative containing the unnatural amino acid (S)-α-hydrazinophenylalanine, was prepared in an effort to examine the stereochemical requirements of the A- site of the ribosome during in vitro protein synthesis. The (S)-α- hydrazinophenylalanine moiety was of interest because it contains two nucleophilic centers, the secondary nitrogen attached to C(α), which is normally acylated during the course of peptide bond formation, and the sterically less hindered primary nitrogen. To determine the position of acylation, (S)-α-hydrazinophenylalanyl-tRNA(Phe) was tested in an Escherichia cull in vitro protein biosynthesizing system lacking elongation factor G, such that only dipeptide products were formed. The dipeptide product mixture was analyzed by HPLC in direct comparison with authentic synthetic standards. The dipeptide assay utilizing (S)-α- hydrazinophenylalanyl-tRNA(Phe) as the A-site tRNA established that the analogue functioned well as an acceptor tRNA; HPLC analysis of the products showed that both dipeptides were formed in approximately equal amounts. When attached to a suppressor tRNA transcript, (S)-α-hydrazinophenylalanine was also incorporated into position 27 of dihydrofolate reductase in an E. coli protein synthesizing system by readthrough of a nonsense codon. This finding expands the currently accepted model of peptide bond formation at the ribosome and adds to the repertoire of peptide-like products shown to form at the peptidyltransferase center of the ribosome.
- Killian, Jennifer A.,Van Cleve, Mark D.,Shayo, Yuda F.,Hecht, Sidney M.
-
p. 3032 - 3042
(2007/10/03)
-
- Stereoselective hetero-claisen rearrangement of camphor derived oxazoline-N-oxides
-
Camphor derived oxazoline-N-oxides in the presence of various acylating agents afforded α-acyloxyoxazolines resulting from a diastereoselective [3,3] rearrangement. The configuration of the newly formed asymmetric center was established by chemical correlation. The observed diastereoselectivity accounts a concerted rather than a stepwise process.
- Dalko, Peter I.,Langlois, Yves
-
p. 2107 - 2110
(2007/10/03)
-
- Polymer-bound p-alkoxybenzyl trichloracetimidates: Reagents for the protection of alcohols as benzyl ethers on solid-phase
-
Wang and Tentagel resins ware converted into their trichloroacetimidate dervatives and used as polymer-bound benzylating reagents for a variety of alcohols. Loading and cleavage proceed in good to excellent yields in the presence of BF3.OEt2 and 1% TFA respectively. The resins have excellent shelf life.
- Hanessian, Stephen,Xie, Fang
-
p. 733 - 736
(2007/10/03)
-
- Macrocyclic inhibitors of penicillopepsin. 1. Design, synthesis, and evaluation of an inhibitor bridged between P1 and P3
-
The macrocyclic peptidyl phosphonate 1-L was designed on the basis of the conformation of an acyclic analogue (4) bound to the aspartic protease penicillopepsin. This material and the two acyclic comparison compounds 2-L and 3 were synthesized and evaluated as inhibitors; their binding affinity was found to be inversely related to the degree of conformational flexibility across the series: 3 (K(i) = 110 μM), 2- L (K(i) = 7.6 μM), 1-L (K(i) = 0.80 μM). NMR methods in conjunction with molecular modeling were used to assign the stereochemical configurations of the precursor 16-L and its diastereomer 16-D and to determine the solution conformations of the macrocyclic ring systems. The conformation of the peptide backbone in 1-L closely approximates that desired for a mimic of the lead inhibitor 4, and it appears that the low-energy conformation of 1-L can be accommodated in the pencillopepsin active site without significant distortion.
- Meyer, J. Hoyt,Bartlett, Paul A.
-
p. 4600 - 4609
(2007/10/03)
-
- Synthesis of optically pure 4-alkenyl- or 4-alkanyl-2-hydroxytetronic acids
-
The present invention relates to a method for synthesis of optically pure 4-alkenyl or 4-alkanyl-2-hydroxytetronic acids from an optically pure aldehyde. The invention further relates to the use of such optically pure compounds as potent inhibitors of pla
- -
-
-
- Building units for N-backbone cyclic peptides. 2. Synthesis of protected N-(ω-thioalkylene) amino acids and their incorporation into dipeptide units
-
A new family of amino acids which contain an ω-thioalkylene group on the N(α)-amino nitrogen was synthesized by alkylation of ω-thioalkylamines with triflates of α-hydroxy acids. The reaction proceeded with inversion of configuration yielding optically pure products. The N(α)-(ω-thioalkylene)amino acids were orthogonally protected to allow their incorporation into peptides by solid-phase peptide synthesis (SPPS) methodology. In addition some of these new protected N(α)-(ω-thioalkylene)amino acids were incorporated into dipeptides by 'solution' techniques.
- Bilan, Gal,Gilon, Chaim
-
p. 10513 - 10522
(2007/10/02)
-
- Conformationally constrained nonpeptide β-turn mimetics of enkephalin
-
The design, synthesis and in vitro biological analysis of a family of conformationally constrained nonpeptide mimetics incorporating a 4→1 β-turn prosthetic unit to examine the proposed biological significance of this conformer is described.
- Gardner, Benjamin,Nakanishi, Hiroshi,Kahn, Michael
-
p. 3433 - 3448
(2007/10/02)
-
- HETEROCYCLIC PEPTIDE RENIN INHIBITORS
-
A renin inhibiting compound of the formula STR1 wherein X is N, O or CH; R 1 is absent or a functional group; A and L are independently selected from absent, C=O, SO 2 and CH 2 ; D is C=O, SO. sub.2 or CH 2 ; Y is N or CH; R 2 is hydrogen, loweralkyl or substituted alkyl; Z is a functional group; R 3 is loweralkyl or substituted alkyl; n is 0 or 1; and T is a mimic of the Leu-Val cleavage site of angiotensinogen; or a pharmaceutically acceptable salt, ester or prodrug thereof.
- -
-
-
- Interconversion of (R) and (S)-α-hydroxy esters: precursors of (S) and (R)-O-benzyl-α-hydroxylamino acid esters of high optical purity.
-
(R)- and (S)-α-hydroxy esters 5 are interconverted via their triflates 6 in high chemical as well as optical yields by reaction with dimethylformamide.The same triflates are efficiently converted into N-hydroxy-α-amino acid derivatives 7 of high optical purity.
- Feenstra, R. W.,Stokkingreef, E. H. M.,Nivard, R. J. F.,Ottenheijm, H. C. J.
-
p. 5583 - 5596
(2007/10/02)
-
- ENZYME-MEDIATED ASYMMETRIC HYDROLYSIS OF α-BENZYLOXYCARBOXYLIC ESTERS
-
Incubation of dl-α-benzyloxycarboxylic esters with grown cells of a bacterium, Corynebacterium equi IFO 3730, afforded the chiral esters of high optical purities via asymmetric hydrolysis.This reaction has been revealed to have a wide applicability to alkene- and arylalkene-carboxylic esters.
- Kato, Yasuo,Ohta, Hiromichi,Tsuchihashi, Gen-ichi
-
p. 1303 - 1306
(2007/10/02)
-
- Substitution of 2-(Sulfonyloxy)carboxylates with Oxygene and Sulfur Nucleophiles without Racemization
-
The ethyl 2-(sulfonyloxy)propionates (S)-1a-c react with phenolates formed from 2 and with carboxylates 8 to give the respective 2-(aryloxy)- (R)-3 and 2-(acyloxy)propionates (R)-9 with inversion of configuration.Due to the high leaving tendency of the triflate group, (S)-1a generally give higher yields of substitution products under milder conditions than the corresponding mesylate (S)-1b and tosylate (S)-1c.In the case of the reaction of malic and succinic acid derivatives only the triflate (S)-10a is converted to the acyloxy compounds (R)-12 with carboxylates 8 atlow temperature (-45 deg C); with the mesylates 10b and the bromide 10d only elimination is observed.Mercaptides and thiophenolates formed from 17 react with (S)-1a-c analogously.With potassium thiocyanate 1a,b react almost exclusively to give the thiocyanate 19; only traces of the corresponding isothiocyanate 20 are obtained.
- Burkard, Ulrike,Effenberger, Franz
-
p. 1594 - 1612
(2016/06/15)
-
- Asymmetric Oxidation of Ester and Amide Enolates Using New (Camphorylsulfonyl)oxaziridines
-
The first asymmetric oxidation of ester and amide lithium enolates 5 to optically active α-hydroxycarbonyl compounds 6 is reported using new, easily prepared, stable (camphorylsulfonyl)oxaziridines (+)-(2R,8aS)-3 and (-)-(2S,8aR)-4.Either enantiomer of 6 can be readily obtained because the configuration of the oxaziridine three-membered ring determines the product stereochemistry.
- Davis, Franklin A.,Haque, M. Serajul,Ulatowski, Terrance G.,Towson, James C
-
p. 2402 - 2404
(2007/10/02)
-