- Formal synthesis of borrelidin: A highly enantio- and diastereoselective access to the Morken's C2-C12 intermediate
-
In contrast to methyl and isobutyl phenyl sulfone, condensing under basic conditions higher alkyl sulfones and trans-2,3-epoxy-butanol 13c (or its O-benzyl and O-silyl derivatives) proved unfeasible, a difficulty that was overcome by using mono ethers of trans-2,3-epoxy-butane-1,4-diol 35c as the electrophilic reagents. Thus, adding excess BuLi to a mixture of the benzyl ether 35b and sulfone ent-12a, a stereodiad sulfone prepared in pure state from the R-Roche ester, via the O-trityloxy-sulfone ent-12c (X-ray), gave, after elimination by column chromatography of the side-formed regioisomer, a diolsulfone that was next converted to sulfone 20 by means of conventional functional-group modifications. Reacting like-wise this sulfone with the parent O-PMB derivative 35a, and then proceeding to the same purification process and function adjustment, delivered the title fragment in virtually pure state.
- Gembus, Vincent,Karmazin, Lydia,Uguen, Daniel,Zoller, Thomas
-
supporting information
p. 359 - 380
(2019/02/25)
-
- Novel autophagy modulators: Design and synthesis of (+)-epogymnolactam analogues and structure-activity relationship
-
(+)-Epogymnolactam (1) was discovered as a novel autophagy inducer from a culture of Gymnopus sp. in our laboratory. To determine structure-activity relationships among (+)-epogymnolactam analogues comparing with cerulenin (2), we synthesized 5 analogues
- Ueda, Kazuki,Okado, Yuji,Shigetomi, Kengo,Ubukata, Makoto
-
p. 5159 - 5168
(2018/09/27)
-
- Stereoselective synthesis of orthogonally protected 2,3-disubstituted morpholines using a base-catalysed cascade reaction
-
The stereoselective synthesis of differentially protected [3-(hydroxymethyl)morpholin-2-yl]methanols is described, starting from chiral epoxides. The key step involves a one-pot oxazolidinone formation via intramolecular epoxide opening and concomitant cy
- Marlin, Frederic J.
-
supporting information
p. 3078 - 3080
(2017/07/17)
-
- HIV PROTEASE INHIBITORS
-
The present invention is directed to 2,5,6-substituted morpholine derivatives and their use in the inhibition of HIV protease, the inhibition of HIV replication, the prophylaxis of infection by HIV, the treatment of infection by HIV, and the prophylaxis,
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Page/Page column 37
(2015/07/07)
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- Stereoselective total synthesis of oplopandiol, oploxyne A, and oploxyne B
-
A stereoselective total synthesis of oplopandiol, oploxyne A, and (-)-oploxyne B is described. The key reactions include Sharpless asymmetric epoxidation, d-proline catalyzed aminoxylation, Cadiot-Chodkiewicz cross-coupling reaction, m-CPBA induced substrate-controlled stereoselective epoxidation, and Lewis acid catalyzed stereo- and regioselective ring-opening of epoxide.
- Reddy, B.V. Subba,Nageshwar Rao,Kumaraswamy,Yadav
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p. 4590 - 4592
(2014/12/10)
-
- Palladium hydroxide catalyzed transformation of primary propargylic alcohols into aldehydes: Application to the synthesis of the tetrahydrofuran core
-
A palladium-catalyzed one-pot, two-step sequence involving redox isomerization/reduction of primary propargylic alcohols into the corresponding aldehydes has been achieved at room temperature for the first time in good to excellent yields under mild conditions. The functional group compatibility in this reaction is studied and this new methodology has been successfully applied in the synthesis of the 2,5-trans-tetrahydrofuran ring system of amphidinolides. It is noteworthy that aromatic substituted propargylic alcohols gave a mixture of unsaturated and saturated aldehydes, whereas aliphatic propargylic alcohols gave only saturated aldehydes. Georg Thieme Verlag Stuttgart · New York.
- Sabitha, Gowravaram,Reddy, A.Yagundar,Nayak, Sambit,Yadav, Jhillu S.
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scheme or table
p. 1657 - 1662
(2012/07/03)
-
- Organocatalytic asymmetric epoxidation and tandem epoxidation/Passerini reaction under eco-friendly reaction conditions
-
An eco-friendly synthesis of highly functionalized epoxides and their incorporation into an organocatalytic multicomponent approach are reported. For this, a modified class of diarylprolinol silyl ethers was designed to enable high catalytic activity in an environmentally benign solvent system. The one-pot procedure showed great efficiency in promoting stereoselective multicomponent transformations in a tandem, 'green' fashion. Because of its non-residual, efficient and selective character, this synthetic design shows promise for large-scale applications in both diversity and target-oriented syntheses. The Royal Society of Chemistry 2012.
- Deobald, Anna Maria,Corrêa, Arlene G.,Rivera, Daniel G.,Paix?o, Márcio Weber
-
p. 7681 - 7684
(2013/04/24)
-
- Highly diastereoselective construction of substituted pyrrolidines: Formal synthesis of (-)-bulgecinine
-
A highly diastereoselective synthesis of substituted pyrrolidines has been achieved starting from nonchiral molecule, allyl bromide, or cis-but-2-ene-1,4-diol. The method involves the asymmetric epoxidation and endo-mode epoxide opening with azide nucleop
- Das, Biswanath,Kumar, Duddukuri Nandan
-
scheme or table
p. 1285 - 1287
(2011/07/09)
-
- Stereocontrolled construction of tetrasubstituted tetrahydrofurans: Synthesis of 2,5-anhydro d-glucitol
-
A highly stereoselective construction of 2,3,4,5-tetrasubstituted tetrahydrofurans has been accomplished by an unusual intramolecular 5-endo-tet cyclization of 2,3-epoxy alcohols involving hydroxyl nucleophile. The method has been utilized for the synthes
- Das, Biswanath,Kumar, Duddukuri Nandan
-
scheme or table
p. 6011 - 6013
(2010/11/21)
-
- Stereoselective total synthesis of (+)-anamarine via cross-metathesis protocol
-
A convergent stereoselective total synthesis of (+)-anamarine via cross-metathesis (CM) protocol starting from 2-butyn-1,4-diol and vinyl lactone is reported. Other key features of the strategy include the use of Sharpless asymmetric epoxidation, Sharples
- Sabitha, Gowravaram,Reddy, C. Nagendra,Gopal, Peddabuddi,Yadav
-
scheme or table
p. 5736 - 5739
(2010/11/16)
-
- Stereoselective formal total synthesis of novel antibiotic (-)-centrolobine
-
A concise and stereoselective formal total synthesis of (-)-centrolobine is achieved utilizing Mioskowski's Lewis acid mediated epoxide opening followed by ring-closing metathesis as the key reaction.
- Mohapatra, Debendra K.,Pal, Rita,Rahaman, Hasibur,Gurjar, Mukund K.
-
body text
p. 219 - 227
(2010/05/03)
-
- Synthesis of N-heterocycles, beta-amino acids, and allyl amines via aza-payne mediated reaction of ylides and hydroxy aziridines
-
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under the basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring closure yields the desired pyrrolidine, thus completing the relay of the 3-membered the 5-membered nitrogen containing ring system. This process takes place with complete transfer of stereochemical fidelity, and can be applied to sterically hindered aziridinols.
- -
-
Page/Page column 17-18
(2009/01/23)
-
- Total Synthesis of rapamycin
-
For over 30 years, rapamycin has generated a sustained and intense interest from the scientific community as a result of its exceptional pharmacological properties and challenging structural features. In addition to its well known therapeutic value as a potent immunosuppressive agent, rapamycin and its derivatives have recently gained prominence for the treatment of a wide variety of other human malignancies. Herein we disclose full details of our extensive investigation into the synthesis of rapamycin that culminated in a new and convergent preparation featuring a macro-etherification/catechol-templating strategy for construction of the macrocyclic core of this natural product.
- Ley, Steven V.,Tackett, Miles N.,Maddess, Matthew L.,Anderson, James C.,Brennan, Paul E.,Cappi, Michael W.,Heer, Jag P.,Helgen, Celine,Kori, Masakuni,Kouklovsky, Cyrille,Marsden, Stephen P.,Norman, Joanne,Osborn, David P.,Palomero, Maria A.,Pavey, John B. J.,Pinel, Catherine,Robinson, Lesley A.,Schnaubelt, Juergen,Scott, James S.,Spilling, Christopher D.,Watanabe, Hidenori,Wesson, Kieron E.,Willis, Michael C.
-
experimental part
p. 2874 - 2914
(2009/12/25)
-
- Solvent-dependent reactivity in porcine pancreatic lipase (PPL)-catalyzed hydrolysis
-
The solvent-dependent enzyme reactivity of porcine pancreatic lipase (PPL)-catalyzed hydrolysis was investigated using trans-3 and cis-(3-(benzyloxymethyl)oxiran-2-yl)methyl acetate 4 as substrates. The conversion efficiency and enantioselectivity of the
- Shen, Liu-Lan,Wang, Fang,Mun, Han-Seo,Suh, Myungkoo,Jeong, Jin-Hyun
-
p. 1647 - 1653
(2008/12/21)
-
- Enantioselective access to a versatile 4-oxazolidinonecarbaldehyde and application to the synthesis of a cytotoxic jaspine B truncated analogue
-
The preparation of the versatile aldehyde 15 via a concise route based on a formal anti-asymmetric aminohydroxylation and its use in a 5-step synthesis of a cytotoxic C12 analogue of the natural anhydrophytosphingosine jaspine B is presented.
- Genisson, Yves,Lamande, Lydia,Salma, Yahya,Andrieu-Abadie, Nathalie,Andre, Chantal,Baltas, Michel
-
p. 857 - 864
(2008/02/09)
-
- Diastereomerically and enantiomerically pure 2,3-disubstituted pyrrolidines from 2,3-aziridin-1-ols using a sulfoxonium ylide: A one-carbon homologative relay ring expansion
-
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring-closure yields the desired pyrrolidine, thus completing the relay of the three-membered to the five-membered nitrogen-containing ring system. This process takes place with complete transfer of stereochemical fidelity and can be applied to sterically hindered aziridinols.
- Schomaker, Jennifer M.,Bhattacharjee, Somnath,Yan, Jun,Borhan, Babak
-
p. 1996 - 2003
(2007/10/03)
-
- ACYCLIC 1,4-DIAMINES AND USES THEREOF
-
This invention relates to novel compounds useful in the treatment of diseases associated with TRPV4 channel receptor. More specifically, this invention relates to certain acyclic diamines, which are agonists of TRPV4 channel receptors.
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-
Page/Page column 42; 112
(2008/06/13)
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- Amine-catalyzed asymmetric epoxidation of α,β-unsaturated aldehydes
-
The direct organocatalytic enantioselective epoxidation of α,β-unsaturated aldehydes with different peroxides is presented. Proline, chiral pyrrolidine derivatives, and amino acid-derived imidazolidinones catalyze the asymmetric epoxidation of α,β-unsatur
- Zhao, Gui-Ling,Ibrahem, Ismail,Sunden, Henrik,Cordova, Armando
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p. 1210 - 1224
(2008/09/17)
-
- Efficient, scalable kinetic resolution of cis-4-benzyloxy-2,3-epoxybutanol
-
A new enzyme catalysed kinetic resolution of cis-4-benzyloxy-2,3- epoxybutanol has been reported. Efficient, scalable separation of the optically active alcohol from its ester derivative has been solved with liquid-liquid and solid-liquid extraction metho
- Faigl, Ferenc,Thurner, Angelika,Battancs, Melinda,Farkas, Ferenc,Poppe, Laszlo,Bodai, Viktoria,Kmecz, Ildiko,Simandi, Bela
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p. 3841 - 3847
(2007/10/03)
-
- Organocatalytic asymmetric epoxidation reactions in water-alcohol solutions
-
The diastereo- and enantioselective organocatalytic epoxidation of α,β-unsaturated aldehydes in aqueous solutions is presented. By the screening of the reaction conditions for the epoxidation of cinnamic aldehyde applying hydrogen peroxide as the oxidant and 2-[bis-(3,5-bis-trifluoromethyl- phenyl)-trimethylsilanyloxy-methyl]-pyrrolidine as the catalyst, a highly stereoselective reaction has been developed. The scope of the diastereo- and enantioselective organocatalytic epoxidation in aqueous solutions is documented by the asymmetric epoxidation of α,β-unsaturated aldehydes with enantioselectivities up to 96% ee. The Royal Society of Chemistry 2005.
- Zhuang, Wei,Marigo, Mauro,Jorgensen, Karl Anker
-
p. 3883 - 3885
(2007/10/03)
-
- Arabinose-derived ketones as catalysts for asymmetric epoxidation of alkenes
-
Readily available arabinose-derived ketones, containing a tunable butane-2,3-diacetal as the steric blocker, displayed increasing enantioselectivity (up to 90% ee) with the size of the acetal alkyl group in catalytic asymmetric epoxidation of trans-disubstituted and trisubstituted alkenes. The stereochemical communication between our ketone catalysts and the alkene substrates is mainly due to steric effect, and electronic effect involving π-π interaction between phenyl groups of substrate and of catalyst did not appear to be operative in our system.
- Shing, Tony K. M.,Leung, Gulice Y. C.,Luk, To
-
p. 7279 - 7289
(2007/10/03)
-
- Studies towards the total synthesis of palau'amine. Formation of 4,5-dihydropyrrole-2-carboxylate intermediates by alkene-enamide ring-closing metathesis
-
A highly functionalized 4,5-dihydropyrrole-2-carboxylate is assembled by alkene-enamide ring-closing metathesis. Subsequent intramolecular azomethine imine dipolar cycloaddition provides a triazacyclopenta[cd]pentalene intermediate of potential use in a t
- Katz, Jason D.,Overman, Larry E.
-
p. 9559 - 9568
(2007/10/03)
-
- Synthesis of diastereomerically and enantiomerically pure 2,3-disubstituted tetrahydrofurans using a sulfoxonium ylide
-
Nucleophilic substitution reactions of 2,3-epoxy alcohols, easily prepared via Sharpless asymmetric epoxidation chemistry, offer access to a wide variety of enantiomerically pure compounds. In this communication, we describe the use of a Payne rearrangement to control regioselectivity in the ring-opening of a series of 2,3-epoxy alcohols with dimethylsulfoxonium methylide to yield diastereomerically and/or enantiomerically pure disubstituted tetrahydrofuran rings. The factors influencing the success and substitution pattern of the THF ring products are discussed, including steric, electronic, and solvent effects. Copyright
- Schomaker, Jennifer M.,Pulgam, Veera Reddy,Borhan, Babak
-
p. 13600 - 13601
(2007/10/03)
-
- Synthetic studies on bafilomycin A1: Stereoselective synthesis of the C12-C17 fragment and its coupling with the C 1-C11 subunit
-
Stereoselective addition of (E)-1-lithio-2-tributylstannylethylene on a chiral cyclic di-t-butylsilyleneketal C14-C17 aldehyde afforded the required Felkin-Anh adduct for the synthesis of the C 12-C17 fragment of bafilomycin A1, the configuration of which was assigned unambiguously. After appropriate coupling with the enantiopure C1-C11 fragment, the C 12-C17 subunit obtained here can be used for the study of the 16-membered macrolide formation either by an acyl activation or an intramolecular Stille reaction. Intermolecular esterification of the 15-OH with an acyl activation of the carboxylic acid of the C1-C11 fragment, in modified Yamaguchi's conditions, affords here an intermediate for examining an intramolecular Stille coupling.
- Quéron, Emmanuelle,Lett, Robert
-
p. 4533 - 4537
(2007/10/03)
-
- Palladium-catalyzed stereospecific epoxide-opening reaction of γ,δ-epoxy-α,β-unsaturated esters with an alkylboronic acid leading to γ,δ-vicinal diols with double inversion of the configuration
-
A palladium-catalyzed stereospecific epoxide-opening reaction of γ,δ-epoxy-α,β-unsaturated esters with an alkylboronic acid leading to γ,δ-vicinal diols is described, which proceeds with retention of the configuration, i.e., via two consecutive SN/s
- Hirai, Atsushi,Yu, Xiao-Qiang,Tonooka, Terumichi,Miyashita, Masaaki
-
p. 2482 - 2483
(2007/10/03)
-
- A regio- and stereodivergent route to all isomers of vic-amino alcohols.
-
Vicinal amino alcohols are substructures in several important natural products. They are also frequently employed ligands in asymmetric synthesis. Many enantioselective syntheses of vic-amino alcohols have been reported, but each structure has required its own synthetic route. This study presents a synthetic strategy leading to all eight possible isomers of a given beta-amino alcohol, starting from vinyl epoxides. The developed strategy focuses on the propensity of vinyl epoxides and vinylaziridines to be selectively ring-opened at the allylic position by suitable hard nucleophiles. Within this strategy, a novel large-scale aminolysis reaction and the synthesis of a trisubstituted N-H vinylaziridine are detailed.
- Olofsson, Berit,Somfai, Peter
-
p. 8574 - 8583
(2007/10/03)
-
- A study on the chelation control in the regioselective opening of 2,3-bifunctionalized epoxides
-
The results obtained in the MgBr2-mediated opening of 2,3-bifunctionalized epoxides are reported. The studies showed that the chelation control of MgBr2 between different functionalities can in some cases be selective.
- Righi, Giuliana,Pescatore, Giovanna,Bonadies, Francesco,Bonini, Carlo
-
p. 5649 - 5656
(2007/10/03)
-
- Regioselective synthesis of 13C1-labeled 2-deoxyribonolactones
-
Syntheses of the five regioselectively 13C1-labeled 5-O-benzyl-2-deoxyribonolactones are described. 13C1-Labeled deoxyribonolactones were prepared by addition of KCN to epoxides 7 and subsequent lactonization of the resulting nitriles. Integration of the independent schemes leading to the five isotopomers of 9 results in an efficient and cost effective preparation of labeled mixtures of 13C mono-labeled deoxyribonolactones. These mixtures are the pivotal intermediates in the preparation of 'population labeled' 13C-labeled nucleoside phosphoramidites for solid-phase oligonucleotide synthesis.
- Hayes, Michael P,Hatala, Paul J,Sherer, Brian A,Tong, Xiaohong,Zanatta, Nilo,Borer, Philip N,Kallmerten, James
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p. 1515 - 1524
(2007/10/03)
-
- First enantioselective non-biological synthesis of asymmetrised tris(hydroxymethyl)methane (THYM*) and bis(hydroxymethyl)acetaldehyde (BHYMA*)
-
An asymmetric synthesis of a chiral non-racemic (O-benzyl, O′-silyl) derivative of the latent C3v-symmetric tris(hydroxymethyl)methane (THYM*) and of the bis(hydroxymethyl)acetaldehyde (BHYMA*) in 6 steps, 38% overall yield and 7 steps, 36% ove
- Izzo, Irene,Scioscia, Matteo,Del Gaudio, Pasquale,De Riccardis, Francesco
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p. 5421 - 5424
(2007/10/03)
-
- Studies directed toward the syntheses of amphidinolides: Formal total synthesis of (-)-amphidinolide P
-
A formal total synthesis of (-)-amphidinolide P (1) has been achieved via an efficient convergent strategy for the stereoselective construction of the two advanced intermediates 2 and 3, used recently by Williams et al. in their synthesis of the same mole
- Chakraborty, Tushar K.,Das, Sanjib
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p. 3387 - 3390
(2007/10/03)
-
- Stereoselective route towards 2,5-disubstituted piperidine alkaloids. Synthesis of (+)-pseudoconhydrine and (±)-epi-pseudoconhydrine
-
This paper describes a new general approach towards functionalized piperidine alkaloids, based on the stereo- and regioselective palladium(0)- catalyzed nucleophilic ring-opening of vinyl epoxides by nitrogen nucleophiles. The latter reaction provides acc
- L?fstedt, Joakim,Pettersson-Fasth, Helena,B?ckvall, Jan-E.
-
p. 2225 - 2230
(2007/10/03)
-
- Heterogeneous asymmetric epoxidation of cis-allylic alcohols: Use of polymer-supported Ti(IV)-catalyst
-
Heterogeneous asymmetric epoxidation of cis-allylic alcohols with titanium isopropoxide and tert-butyl hydroperoxide has been achieved using a branched/crosslinked poly(tartrate ester) ligand. The enantioselectivities and chemical yields obtained are at l
- Karjalainen, Jaana K.,Hormi, Osmo E. O.,Sherrington, David C.
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p. 2019 - 2022
(2007/10/03)
-
- A highly efficient practical method for the synthesis of chiral polyhydroxy-(E,E)-1-chlorodienols and (E)-5-hydroxy enynes
-
An efficient protocol for the synthesis of chiral polyhydroxy-(E, E)-1-chlorodienols and (E)-5-hydroxy enynes from chiral 4,5-epoxy trans allyl chlorides and 4,5-O-isopropylidene allyl chlorides is described by using stoichiometric amount of LiNH2 or LDA in HMPA : THF (1 : 5) useful in the synthesis of biologically active natural products.
- Yadav,Barma,Dutta, Dinah
-
p. 4479 - 4482
(2007/10/03)
-
- Regiochemical control of the ring opening of 1:2-epoxides by means of chelating processes. 10. Synthesis and ring opening reactions of mono- and difunctionalized cis and trans aliphatic oxirane systems
-
The regiochemical outcome of the ring opening of 1:2-epoxides through chelation processes assisted by metal ions, was verified in mono- and difunctionalized aliphatic oxirane systems bearing the heterofunctionality (OR) in an homoallylic and/or allylic relationship to the oxirane ring. The effect of the distance of the OR functionality from the oxirane ring and of the type of protective group on the regiochemical outcome of these systems is examined. In some cases, the use of LiClO4 or Mg(ClO4)2 as the promoting metal salt makes it possible the obtainment of a nice regioalternating process.
- Azzena, Francesca,Calvani, Federico,Crotti, Paolo,Gardelli, Cristina,Macchia, Franco,Pineschi, Mauro
-
p. 10601 - 10626
(2007/10/02)
-
- Regiochemical control of the ring opening of 1,2-epoxides by means of chelating processes.11. Ring opening reactions of aliphatic mono- and difunctionalized cis and trans 2,3- and 3,4-epoxy esters
-
The regiochemical outcome of the ring opening of 1,2-epoxides through chelation processes assisted by metal ions, was verified in the azidolysis of simple aliphatic cis and trans 2,3- and 3,4-epoxy esters and in the corresponding derivatives bearing an ether functionality (OBn) in an allylic relationship to the oxirane ring. The results indicate that the behavior of these epoxides is influenced both by the opening conditions (standard or metal-assisted) and the promoting metal salt [LiClO4 or Mg(ClO4)2]. Copyright
- Azzena, Francesca,Crotti, Paolo,Favero, Lucilla,Pineschi, Mauro
-
p. 13409 - 13422
(2007/10/02)
-
- N-substituted acylamino acid compounds, process for their production and their use
-
The present invention provides an N-substituted acylamino acid compound of the formula: STR1 a process for their production and pharmaceutical uses, and intermediates useful for their production.
- -
-
-
- Chemoenzymatic Synthesis of Homoazasugars
-
A chemoenzymatic approach for the synthesis of homoazasugars is described, utilizing an aldolase to catalyse the key asymmetric aldol addition reaction.This approach is illustrated by the synthesis of β-D-homomannonojirimycin (11) using D-fructose diphosp
- Henderson, Ian,Laslo, Karen,Wong, Chi-Huey
-
p. 359 - 362
(2007/10/02)
-
- Studies towards the total synthesis of rapamycin: Preparation of the C10-C17 carbon unit
-
The preparation of the C10 - C17 carbon unit of the immunosuppressive agent rapamycin is reported via two routes leading to the substituted lactone 4.
- Ley, Steven V.,Norman, Joanne,Pinel, Catherine
-
p. 2095 - 2098
(2007/10/02)
-
- A Tellurium Transposition Route to Allylic Alcohols: Overcoming Some Limitations of the Sharpless-Katsuki Asymmetric Epoxidation
-
Good yields of enantiomeric allylic alcohols can be obtained in high enantiomeric excess (ee) by combining Sharpless-Katsuki asymmetric epoxidation process (SAE) with tellurium chemistry.The advantages of the tellurium process are as follows: (1) the 50percent yield limitation on the allylic alcohol in the Sharpless kinetic resolution (SKR) can be overcome; (2) allylic tertiary alcohols which are unsatisfactory substrates in the SKR can be obtained in high optical purity; (3) optically active secondary allylic alcohols with tertiary alkyl substituents (e.g. tert-butyl) at C-1 can be obtained in high ee; (4) optically active sterically congested cis secondary alcohols can be obtained in high ee; and (5) the nuisance of the slow SAE of some vinyl carbinols can be avoided.The key step in the reaction sequence is either a stereospecific 1,3-transposition of double bond and alcohol functionalities or an inversion of the alcohol configuration with concomitant deoxygenation of the epoxide function in epoxy alcohols.Trans secondary allylic alcohols can be converted to cis secondary allylic alcohols by way of erythro epoxy alcohols (glycidols); threo glycidyl derivatives are converted to trans secondary allylic alcohols.These transformations are accomplished by the action of telluride ion, generated in situ from the element, on a glycidyl sulfonate ester.Reduction of elemental Te is conveniently done with rongalite (HOCH2SO2Na) in an aqueous medium.This method is satisfactory when Te2- is required to attack at primary carbon site of a glycidyl sulfonate.In cases where Te2- is required to attack a secondary carbon site, reduction of the tellurium must be done with NaBH4 or LiEt3BH.Elemental tellurium is precipitated during the course of the reactions and can be recovered and reused.
- Dittmer, Donald C.,Discordia, Robert P.,Zhang, Yanzhi,Murphy, Christopher K.,Kumar, Archana,et al.
-
p. 718 - 731
(2007/10/02)
-
- A Formal Synthesis of Aplysiatoxin: Enantioselective Synthesis of Kishi's Aldehyde
-
This paper describes the enantioselective synthesis of key fragments (12,18,24, and 35) for the synthesis of aplysiatoxin (1a), a potent cancer promoter, and their convergent assembly to Kishi's aldehyde (2).Since 2 has already been transformed into 1a in
- Okamura, Hiroaki,Kuroda, Satoru,Ikegami, Satoru,Tomita, Kenji,Sugimoto, Yu-ichi,et al.
-
p. 10531 - 10554
(2007/10/02)
-
- Diastereoface differentiation in addition of lithium enolates to chiral α, β-epoxyaldehydes
-
The aldolisation reaction of lithium ester enolates with chiral α,β-epoxyaldehydes 2a-2f has been investigated. The reaction proceeds with diastereofacial preference in favour of the anti isomer (anti: syn ≈ 4:1) and can be greatly enhanced in the case of
- Escudier, Jean-Marc,Baltas, Michel,Gorrichon, Liliane
-
p. 5253 - 5266
(2007/10/02)
-
- Syntheses of two pairs of enantiomeric C18-sphingosines and a palmitoyl analogue of gaucher spleen glucocerebroside
-
Sixteen kinds of chiral C4-epoxides [(-)-10a-d,(+)-10a-d,(-)-11a-d,(+)-11a-d], which are synthons in our synthetic strategy for complex lipids, have been prepared from (2Z)-2-butene-1,4-diol (6) by employing a Sharpless asymmetric epoxidation. By using the chiral C4-epoxides [(+)-10a,(-)-10a,(-)-11a,(+)-11a] as starting compounds, two pairs of enantiomeric (D-erythro, L-erythro, D-threo, and L-threo)-C18-sphingosines (1, 2, 3, 4) have been synthesized via a regioselective ring-opening of the epoxide ring with azide anion followed by reduction of the azide group to an amino group and a Wittig reaction. Furthermore, D-erythro-C18-sphingosine (1) has been converted to a palmitoyl analogue (5a) of Gaucher spleen glucocerebroside (5) through a reaction pathway including successive condensations with palmitic acid and D-glucose.
- Shibuya,Kawashima,Narita,Ikeda,Kitagawa
-
p. 1154 - 1165
(2007/10/02)
-
- A New Approach to the Synthesis of Chiral Vinyl Carbinols from 2,3-Epoxy Alcohols
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The regioselective opening with benzoic acid of 2,3-epoxy alcohols obtained from the asymmetric epoxidation of 2,3-allylic alcohols, and deoxygenation of the resulting diol benzoates provides an effective, general and simple method to convert chiral 2,3-epoxy alcohols, into vinyl carbinols without the loss of any optical purity.
- Martin, Victor S.,Ode, Jesus M.,Palazon, Jose M.,Soler, Marcos A.
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p. 573 - 580
(2007/10/02)
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- AN ENANTIOCONTROLLED ROUTE TO THE C11-17 SEGMENT OF MYCINAMICINS III AND IV
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An enantiocontrolled route to the common C11-17 segment (2) of mycinamicins III (1a) and IV (1b) has been developed starting from the chiral α-hydroxyacetylene (6) obtained from (E)-4-benzyloxybut-2-en-1-ol (3).
- Takano, Seiichi,Sekiguchi, Yoshinori,Ogasawara, Kunio
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p. 743 - 756
(2007/10/02)
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- ENANTIOSELECTIVE SYNTHESIS OF FOUR ISOMERIC BUILDING BLOCKS USEFUL IN THE SYNTHESIS OF 2-NOR-LEUKOTRIENE ANALOGUES
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We report, in this letter, the enantioselective synthesis of four isomeric functionalized epoxides (3a, 3b, 3c and 3d) which are useful building blocks for the synthesis of 2-nor-leukotriene analogues.All four epoxides are formally derived from a single n
- Bellamy, F. D.,Bondoux, M.,Boubia, B.,Dodey, P.,Mioskowski, C.
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p. 355 - 358
(2007/10/02)
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- N-ACYLAMINO ACID DERIVATIVES AND THEIR PHARMACEUTICAL COMPOSITIONS
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An N-acylamino acid derivative of the formula: STR1 wherein the substituents are herein defined or a salt thereof, which is useful as hypotensive drugs.
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- Alkylation of 2-Oxy-Substituted 1-Sulfonylallyl and 1-Sulfonylvinyl Anions. New Routes to Functionalized Carbocycles and Dihydrofurans
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Alkylation of the anion derived from 2-phenoxy-3-(phenylsulfonyl)-1-propene proceeds α to the phenylsulfonyl group and affords cyclic products from 1,ω-dihalides.Reaction of the monoalkylated products, in which a suitably positioned olefinic or acetylenic unit is present, with sodium benzenesulfinate-acetic acid gives functionalized acetylcyclopentenes and cyclohexenes via C-C bond formation from the allyl cation-sulfinate ion pair.In the vinyl sulfone series, deprotonation of (E)- or (Z)-2-alkoxyvinyl phenyl sulfones rapidly affords the more stable (E)-lithio derivative, an acetaldehyde anion equivalent which reacts normally with aldehydes, ketones, alkyl halides, and epoxides.The latter process may be effected in an intramolecular fashion.Thus, (E)-(2-phenylsulfonyl)vinyl ethers of 2,3-epoxy alcohols cyclize on treatment with amide bases to afford dihydrofurans whose stereochemistry is fully defined by that of the starting epoxy alcohol.
- Padwa, Albert,Bullock, William H.,Dyszlewski, Andrew D.,McCombie, S. W.,Shankar, B. B.,Ganguly, A. K.
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p. 3556 - 3564
(2007/10/02)
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- SYNTHESIS OF OPTICALLY ACTIVE γ-CYANO-β,γ-EPOXY ALCOHOLS AND SECONDARY γ-CYANO ALLYLIC ALCOHOLS
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The Sharpless asymmetric epoxidation of 3-cyanoallyl alcohol (4-hydroxy-2-butenecarbonitrile, 6) afforded a potentially useful chiral building block, 3-cyano-2,3-epoxypropan-1-ol (7).Kinetic resolution of the secondary γ-cyano allylic alcohol (rac-3) provided an efficient method for synthesis of optically active 3.The epoxidation of optically active 3 to γ-cyano-α,β-epoxy alcohol 5 was also reported.
- Yamakawa, Isao,Urabe, Hirokazu,Kobayashi, Yuichi,Sato, Fumie
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p. 2045 - 2048
(2007/10/02)
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- Cyclofunctionalisation of epoxyalcohol derivatives. 4. Cyclisation of sulfonylacetate dianions: A synthesis of 'MeBMT'.
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α,α-Dianions, derived from arenesulfonylacetate esters of 2,3-epoxyalcohols, cyclised to give 3-arenesulfonyl-4-(1-hydroxyalkyl)-γ-butyrolactones. Dianion fragmentation to regenerate the epoxyalcohol was a competing, substrate-dependent process. Sulfonylactone (9) was elaborated efficiently to an advanced intermediate for the unusual aminoacid 'MeBMT' (5), and also to stereodefined cyclopropane derivatives.
- McCombie,Shankar,Ganguly
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p. 7029 - 7032
(2007/10/02)
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- Enantiodivergent Route to the Aromatic Bisabolane Sesquiterpenes via a Chiral Acetylene Alcohol
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Efficient preparation and practical utilization of (R)-1-benzyloxy-3-butyn-2-ol have been established.Treatment of (2S,3S)-4-benzyloxy-2,3-epoxybutyl chloride, obtained via the Sharpless epoxidation, with n-butyllithium afforded (R)-1-benzyloxy-3-butyn-2-
- Takano, Seiichi,Sugihara, Takumichi,Samizu, Kiyohiro,Akiyama, Masashi,Ogasawara, Kunio
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p. 1781 - 1784
(2007/10/02)
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