cas 155934-55-7, D-erythro-Pent-4-enose, 4,5-dideoxy-2,3-O-(1-methylethylidene)- (9CI)

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A chiron approach to the total synthesis of cytotoxic (+)-muricatacin and (+)-5-epi-muricatacin from d-ribose
A chiron approach strategy toward the total synthesis of (+)-muricatacin and (+)-5-epi-muricatacin starting from commercially available and inexpensive d-ribose through the key intermediate (S)-5-((R)-1-hydroxyallyl)furan-2(5H)-one has been disclosed.
Ghosal, Partha,Kumar, Vikas,Shaw, Arun K.
p. 41 - 44
(2010)
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A short alternative preparation of the bengazoles polyol side-chain segment
A new short and efficient synthesis of the bengazoles side chain is reported using a sequential Grignard addition-hydroboration approach on a readily available d-ribose derivative.
Gallos, John K.,Stathakis, Christos I.,Salapassidou, Maria J.,Grammatoglou, Constantinos E.,Koumbis, Alexandros E.
p. 744 - 748
(2007)
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Stereoselective Total Synthesis of Arundinolides A and B
The efficient and enantioselective syntheses of arundinolides A and B have been accomplished for the first time from chiral pool methyl-2,3- O -isopropylidene-β- d -ribofuranoside and d -ethyl lactate. The key features of the total synthesis are intramolecular crotonyl migration and NaBH 4 -CuCl catalyzed regioselective reduction and cross-metathesis reaction.
Chang, Caizhu,Dong, Zhi-Bing,Du, Yuguo,Geng, Jialin,Liu, Jun,Liu, Yinxin
p. 1576 - 1584
(2020)
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MEAYAMYCIN ANALOGUES AND METHODS OF USE
Compounds according to formula (I), where R is as defined herein, have anti-cancer properties.
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(2021/10/15)

Total Synthesis of Meayamycin and O-Acyl Analogues
A short, scalable total synthesis of meayamycin is described by an approach that entails a longest linear sequence of 12 steps (22 steps overall) from commercially available chiral pool materials (ethyl l-lactate, BocNH-Thr-OH, and d-ribose) and introduces the most straightforward preparation of the right-hand subunit detailed to date. The use of the approach in the divergent synthesis of a representative series of O-acyl analogues is exemplified.
Boger, Dale L.,Chanda, Prem B.,Chowdari, Naidu S.,Gangwar, Sanjeev,Gartshore, Christopher,Momirov, Jelena,Sarkar, Anindya,Tadano, Shinji,Vite, Gregory D.,Zhang, Qian
(2020/11/18)

A novel and environmental friendly synthetic route for hydroxypyrrolidines using zeolites
A critical step in the synthesis of the hydroxypyrrolidines, 1,4-dideoxy-1,4-imino-L-lyxitol and 1,4-dideoxy-1,4-imino-D-lyxitol, from the corresponding D-sugars is the synthesis of O-methyl 2,3-O-isopropylidenepentofuranoses. Instead of applying homogeneous catalysis process with conventional inorganic acid catalysts like HCl and HClO4, it was found that heterogeneous catalysis using zeolites could be used for the one-pot synthesis of O-methyl 2,3-O-isopropylidenepentofuranoses directly from D-sugars, MeOH and acetone at mild condition. The best catalyst was H-beta zeolite containing a Si/Al molar ratio of 150, where a yield of >83% was obtained. The overall yields of the five-step procedure to 1,4-dideoxy-1,4-imino-L-lyxitol and 1,4-dideoxy-1,4-imino-D-lyxitol were 57% and 50%, respectively. This synthetic procedure has several advantages such as competitive overall yield, reduced number of steps, and mild reaction conditions. Furthermore, the zeolite catalyst can be easily recovered from the reaction mixture and reused with no loss of activity.
Fan,Chuah,Jaenicke, Stephan
p. 103 - 114
(2018/12/13)

Synthesis of N-alkyl substituted iminosugars from D-ribose
An effective and facile method for the synthesis of N-alkylated hydroxylpyrrolidine and hydroxylpiperidine is described. A number of N-alkyl substituted iminosugars were prepared using iodine-induced intramolecular cyclization of acyclic alkenylamines as key step.
Wang, Haibo,Pan, Yang,Tang, Qin,Zou, Wei,Shao, Huawu
supporting information
p. 73 - 75
(2017/10/26)

South (S)- and north (N)-methanocarba-7-deazaadenosine analogues as inhibitors of human adenosine kinase
Adenosine kinase (AdK) inhibitors raise endogenous adenosine levels, particularly in disease states, and have potential for treatment of seizures, neurodegeneration, and inflammation. On the basis of the South (S) ribose conformation and molecular dynamics (MD) analysis of nucleoside inhibitors bound in AdK X-ray crystallographic structures, (S)- and North (N)-methanocarba (bicyclo[3.1.0]hexane) derivatives of known inhibitors were prepared and compared as human (h) AdK inhibitors. 5′-Hydroxy (34, MRS4202 (S); 55, MRS4380 (N)) and 5′-deoxy 38a (MRS4203 (S)) analogues, containing 7- and N6-NH phenyl groups in 7-deazaadenine, robustly inhibited AdK activity (IC50 ～ 100 nM), while the 5′-hydroxy derivative 30 lacking the phenyl substituents was weak. Docking in the hAdK X-ray structure and MD simulation suggested a mode of binding similar to 5′-deoxy-5-iodotubercidin and other known inhibitors. Thus, a structure-based design approach for further potency enhancement is possible. The potent AdK inhibitors in this study are ready to be further tested in animal models of epilepsy.
Toti, Kiran S.,Osborne, Danielle,Ciancetta, Antonella,Boison, Detlev,Jacobson, Kenneth A.
supporting information
p. 6860 - 6877
(2016/08/05)

Identification of a cytotoxic molecule in heat-modified citrus pectin
Modified forms of citrus pectin possess anticancer properties. However, their mechanism of action and the structural features involved remain unclear. Here, we showed that citrus pectin modified by heat treatment displayed cytotoxic effects in cancer cells. A fractionation approach was used aiming to identify active molecules. Dialysis and ethanol precipitation followed by HPLC analysis evidenced that most of the activity was related to molecules with molecular weight corresponding to low degree of polymerization oligogalacturonic acid. Heat-treatment of galacturonic acid also generated cytotoxic molecules. Furthermore, heat-modified galacturonic acid and heat-fragmented pectin contained the same molecule that induced cell death when isolated by HPLC separation. Mass spectrometry analyses revealed that 4,5-dihydroxy-2-cyclopenten-1-one was one cytotoxic molecule present in heat-treated pectin. Finally, we synthesized the enantiopure (4R,5R)-4,5-dihydroxy-2-cyclopenten-1-one and demonstrated that this molecule was cytotoxic and induced a similar pattern of apoptotic-like features than heat-modified pectin.
Leclere, Lionel,Fransolet, Maude,Cambier, Pierre,El Bkassiny, Sandy,Tikad, Abdellatif,Dieu, Marc,Vincent, Stéphane P.,Van Cutsem, Pierre,Michiels, Carine
p. 39 - 51
(2015/11/09)

Diversity-Oriented Synthesis of cis -3,4-Dihydroxylated Piperidine and Its Higher Saturated and Unsaturated Homologues from d -Ribose and Their Glycosidase-Inhibition Study 1
The synthesis of six-, seven-, and eight-membered cis-dihydroxy azacycles has been accomplished from d-ribose using Vasella reductive amination as a key step and utilization of hydroboration-oxidation, Mitsunobu reaction, and ring-closing metathesis (RCM) reactions in a facile manner. These homologous dihydroxylated heterocyclic scaffolds were subjected to the glycosidase inhibition assays. However, only a moderate inhibitory activity for three out of five compounds was observed against α-glucosidases with a high degree of selectivity.
Ajay, Sama,Arora, Inderpreet,Saidhareddy, Puli,Shaw, Arun K.
p. 2721 - 2725
(2016/11/30)

Chiral approach to total synthesis of phytotoxic and related nonenolides: (Z)-isomer of (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone, herbarumin-III and their C-9 epimers
A new and efficient strategy has been developed for the stereoselective total synthesis of nonenolides: (Z)-isomer of (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone, herbarumin-III and their C-9 epimers starting from D (?) ribose. The synthesis includes the coupling of the alcohol and acid fragments of the molecules, employing Yamaguchi esterification protocol followed by intramolecular ring closure metathesis. The method has efficiently constructed the 10-membered lactone skeleton of the compounds with proper stereogenic centers containing appropriate functionalities.
Maram, Lingaiah,Parigi, Raghavendar Reddy,Das, Biswanath
p. 7135 - 7142
(2016/10/22)

Compound a preparation (1R, 2S, 6S, 7S) - 4, 4 - dimethyl -9 - phenylmethyl - 3, 5, 8 - trioxa -9 - aza tricyclic[5.2.1.02.6][...] method
The invention discloses a method for preparing a compound (1R,2S,6S,7S)-4,4-dimethyl-9-benzyl-3,5,8-trioxa-9-azatricyclo[5.2.1.0]decane. The method comprises steps: (1) mixing a compound with the chemical structure shown as a formula 1 and zinc in a protic solvent, so as to obtain a compound with the chemical structure shown as a formula 2; (2) mixing the compound with the chemical structure shown as the formula 2 and benzylhydroxylamine or a salt thereof in a protic solvent in the presence of an inorganic base, so as to obtain a compound with the chemical structure shown as a formula 3, wherein the inorganic base is selected from sodium carbonate, potassium carbonate or sodium bicarbonate; and (3) refluxing the compound with the chemical structure shown as the formula 3 in chlorobenzene in the presence of a base, so as to obtain a compound with the chemical structure shown as a formula 4, wherein the base is selected from potassium carbonate, sodium carbonate, sodium bicarbonate, pyridine and triethylamine.
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Paragraph 0044; 0077; 0078; 0079

(2016/10/09)

Doubly diastereoselective conjugate additions of the antipodes of lithium N-benzyl-N-(α-methylbenzyl)amide to enantiopure ε-O-protected α,β-unsaturated esters derived from d-ribose
Enantiopure ε-O-silyloxy- and ε-O-benzyloxy-α,β- unsaturated esters derived from d-ribose, each containing a cis-dioxolane unit, display excellent (≥95:5 dr) levels of diastereofacial directing ability upon conjugate addition of achiral lithium N-benzyl-N-isopropylamide. In contrast to the corresponding enantiopure ε-O-silyloxy-α,β-unsaturated ester derived from l-tartaric acid, which contains a trans-dioxolane unit, the conjugate additions of the antipodes of lithium N-benzyl-N-(α- methylbenzyl)amide to its cis-configured counterpart result in doubly diastereoselective 'matched' and 'mismatched' reaction pairings in which the inherent reagent control serves to augment or oppose, respectively, the established substrate diastereocontrol.
Davies, Stephen G.,Foster, Emma M.,Lee, James A.,Roberts, Paul M.,Thomson, James E.
p. 534 - 546
(2014/05/06)

SYNTHESIS OF TRIAZOLOPYRIMIDINE COMPOUNDS
The present invention relates to the field of organic synthesis and describes the synthesis of specific intermediates suitable for the preparation of triazolopyrimidine compounds such as ticagrelor.
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(2013/07/05)

Synthesis of Aminocyclopentanetriol Derivatives
The present invention relates to the field of organic synthesis and describes the synthesis of specific intermediates suitable for the preparation of triazolopyrimidine compounds such as ticagrelor. The present invention provides in particular a process for the preparation of a compound of formula V comprising: a) providing a compound of formula IV , and b) reducing the compound of formula IV with activated zinc in the presence of copper to give the compound of formula V.
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(2014/01/07)

Preparation of anti -vicinal amino alcohols: Asymmetric synthesis of d - Erythro -sphinganine, (+)-spisulosine, and d - Ribo -phytosphingosine
Two variations of the Overman rearrangement have been developed for the highly selective synthesis of anti-vicinal amino alcohol natural products. A MOM ether-directed palladium(II)-catalyzed rearrangement of an allylic trichloroacetimidate was used as the key step for the preparation of the protein kinase C inhibitor d-erythro-sphinganine and the antitumor agent (+)-spisulosine, whereas the Overman rearrangement of chiral allylic trichloroacetimidates generated by the asymmetric reduction of an α,β-unsaturated methyl ketone allowed rapid access both to d-ribo-phytosphingosine and l-arabino-phytosphingosine.
Calder, Ewen D. D.,Zaed, Ahmed M.,Sutherland, Andrew
p. 7223 - 7233
(2013/08/23)

Synthesis and biological evaluation of ticagrelor derivatives as novel antiplatelet agents
Ticagrelor (1) is the first reversible P2Y12 receptor antagonist blocking adenine diphosphate (ADP)-induced platelet aggregation with rapid onset and offset of effects. In this study, synthesis of ticagrelor and its derivatives has been accomplished in a convergent way. The compound design was based on modifications of ticagrelor and its major metabolite (33) in order to ameliorate their pharmacokinetic properties and dosing profile. The final compounds (1a-g, 35a-g) were evaluated for their inhibitory effect on ADP-induced platelet aggregation in rats. The assay results showed that some compounds (e.g., 1b, 1d, 33, 35b, 35f) exhibited comparable potency with that of ticagrelor.
Zhang, Hao,Liu, Jun,Zhang, Luyong,Kong, Lingyi,Yao, Hequan,Sun, Hongbin
supporting information; experimental part
p. 3598 - 3602
(2012/07/14)

Synthesis of 4a-carba-β-l-lyxofuranose, 4a-carba-β-l- arabinofuranose and 2,2,5-trimethyl-3a,6a-dihydro-cyclopenta[1,3]dioxol-4-one using Mn/CrCl3 mediated domino reactions and ring closing metathesis
A common method for the synthesis of 4a-carba-β-l-lyxofuranose and 4a-carba-β-l-arabinofuranose from d-mannose and 2,2,5-trimethyl-3a,6a- dihydro-cyclopenta[1,3]dioxol-4-one from d-ribose is described using catalytic Nozaki-Hiyama-Kishi (NHK) conditions and ring closing metathesis (RCM). In this transformation, ω-deoxy-ω-iodo manno/ribo furanoside undergoes reductive elimination in the presence of Mn/CrCl3 to give the corresponding olefin-aldehyde which was trapped by nucleophile under the same conditions to afford the desired diolefinic species. The ring closing metathesis reaction on these diolefinic species with Grubbs second generation catalyst produced the required carbocycles.
Mishra, Girija Prasad,Kumar, Bejugam Santhosh,Venkateswara Rao, B.
p. 1161 - 1169,9
(2020/09/09)

Total synthesis of (+)-cladospolide A
A stereoselective total synthesis of (+)-cladospolide A from d-ribose is described. Key features of the synthesis include olefin cross metathesis and Yamaguchi lactonization. Georg Thieme Verlag Stuttgart New York.
Prasad, Kavirayani R.,Revu, Omkar
experimental part
p. 2243 - 2248
(2012/10/08)

On the origins of diastereoselectivity in the conjugate additions of the antipodes of lithium N-benzyl-(N-α-methylbenzyl)amide to enantiopure cis- and trans-dioxolane containing α,β-unsaturated esters
"Matching" and "mismatching" effects in the doubly diastereoselective conjugate additions of the antipodes of lithium N-benzyl-(N-α-methylbenzyl)amide to enantiopure cis- and trans-dioxolane containing α,β-unsaturated esters have been investigated. High levels of substrate control were established first upon conjugate addition of achiral lithium N-benzyl-N-isopropylamide to both tert-butyl (S,S,E)-4,5-O- isopropylidene-4,5-dihydroxyhex-2-enoate and tert-butyl (4R,5S,E)-4,5-O- isopropylidene-4,5-dihydroxyhex-2-enoate. However, upon conjugate addition of lithium (R)-N-benzyl-(N-α-methylbenzyl)amide and lithium (S)-N-benzyl-(N-α-methylbenzyl)amide to these substrates, neither reaction pairing reinforced the apparent sense of substrate control. These reactions do not, therefore, conform to the classical doubly diastereoselective "matching" or "mismatching" pattern usually exhibited by this class of reaction. A comparison of these reactions with the previously reported doubly diastereoselective conjugate addition reactions of lithium amide reagents to analogous substrates is also discussed.
Davies, Stephen G.,Foster, Emma M.,Frost, Aileen B.,Lee, James A.,Roberts, Paul M.,Thomson, James E.
p. 6186 - 6200
(2012/09/05)

Domino reaction: Pd(II)-catalyzed cyclization of unsaturated polyols and cross-coupling
The Pd-catalyzed cyclization and cross-coupling of hydroxylated alkenes in domino reactions are described. The alkenols undergo Pd-catalyzed cyclization and subsequent cross-coupling reactions with aryl bromides to afford (poly)hydroxylated tetrahydrofura
Lasikova, Angelika,Dohanosova, Jana,Hlavinova, Lucia,Toffano, Martial,Vo-Thanh, Giang,Kozisek, Jozef,Gracza, Tibor
experimental part
p. 818 - 827
(2012/09/25)

USE OF THE IRRITATING PRINCIPAL OLEOCANTHAL IN OLIVE OIL, AS WELL AS STRUCTURALLY AND FUNCTIONALLY SIMILAR COMPOUNDS
The invention provides oleocanthal analogs and methods of using oleocanthals in various formulations including, food additives; pharmaceuticals; cosmetics; animal repellants; and discovery tools for mammalian irritation receptor genes, gene products, alleles, splice variants, alternate transcripts and the like.
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(2011/02/18)

Thioimidate N-oxides: From nature to synthetic pathways
Inspired by the unexpected reactivity of desulfated naturally occurring glucoraphenin, methods to synthesize thioimidate N-oxides (TIO) have been devised on simple or carbohydrate templates. Either through halocyclization or under Mitsunobu conditions, the starting thiohydroximates cyclized to generate efficiently the corresponding TIO. Georg Thieme Verlag Stuttgart ? New York.
Schleiss, Julie,Cerniauskaite, Deimante,Gueyrard, David,Iori, Renato,Rollin, Patrick,Tatibou?t, Arnaud
scheme or table
p. 725 - 728
(2010/06/22)

Palladium-catalyzed coupling reactions of thioimidate N-oxides: Access to α-alkenyl- And α-aryl-functionalized cyclic nitrones
(Figure Presented) Surprisingly useful are thioimidate Noxides in the preparation of aryl- and vinylsubstituted cyclic ketonitrones through the Liebeskind-Srogl reaction. This novel synthetic approach appears to be efficient and have a broad scope (see scheme).
Schleiss, Julie,Rollin, Patrick,Tatiboueet, Arnaud
scheme or table
p. 577 - 580
(2010/04/05)

Total synthesis of the phytotoxic stagonolides A and B
The chemo-enzymatic and covergent synthesis of stagonolide B and the synthesis of stagonolide A, a phytotoxic 10-membered lactone have been achieved starting from d-ribose with overall yields of 25% and 8.7%, respectively. The synthesis contained simple steps in developing three centers' key intermediates, namely the enzymatic (Novozyme-435) resolution of a propargylic alcohol followed by macrolactonization and RCM.
Prabhakar, Peddikotla,Rajaram, Singanaboina,Reddy, Dorigondla Kumar,Shekar, Vanam,Venkateswarlu, Yenamandra
experimental part
p. 216 - 221
(2010/05/18)

Total synthesis of aigialomycin D using a Ramberg - Baecklund/ RCM strategy
The bioactive resorcylic acid lactone aigialomycin D (1) has been synthesized by a novel combination of ring-closing metathesis (RCM) and Ramberg - Baecklund reactions. This synthetic strategy enables the Cl - C2 alkene to be masked as a sulfone during formation of the macrocycle by ring closing metathesis at the C7 - C8 olefin, thus avoiding competing formation of a cyclohexene. A subsequent Ramberg-Baecklund reaction efficiently produces the C1- C2 E-alkene. This combined RCM/ Ramberg-Baecklund reaction strategy should be widely applicable to the synthesis of maerocyclic dienes.
Baird, Lynton J.,Timmer, Mattie S. M.,Teesdale-Spittle, Paul H.,Harvey, Joanne E.
supporting information; experimental part
p. 2271 - 2277
(2009/08/07)

USE OF THE IRRITATING PRINCIPAL OLEOCANTHAL IN OLIVE OIL, AS WELL AS STRUCTURALLY AND FUNCTIONALLY SIMILAR COMPOUNDS
The invention provides methods of synthesizing the purified enantiomers of oleocanthal. The invention further provides methods of using oleocanthals in various formulations including, food additives; pharmaceuticals; cosmetics; animal repellants; and discovery tools for mammalian irritation receptor genes, gene products, alleles, splice variants, alternate transcripts and the like.
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(2009/04/24)

Synthesis of gabosine A and N from ribose by the use of ring-closing metathesis
A concise synthetic route is described for the synthesis of gabosine A and N. The key step uses a zinc-mediated tandem reaction where methyl 5-deoxy-5-iodo-2,3-O-isopropylidene-β-D-ribofuranoside is fragmented to give an unsaturated aldehyde which is ally
Monrad, Rune Nygaard,Fanefjord, Mette,Hansen, Flemming Gundorph,Jensen, N. Michael E.,Madsen, Robert
experimental part
p. 396 - 402
(2009/07/25)

Doubly diastereoselective conjugate addition of homochiral lithium amides to homochiral α,β-unsaturated esters containing cis- and trans-dioxolane units
As part of a long-term goal directed towards the ab initio asymmetric synthesis of unnatural amino sugars, the doubly diastereoselective conjugate addition reactions of the antipodes of lithium N-benzyl-N-(α-methylbenzyl) amide to a range of homochiral α,β-unsaturated esters containing cis- and trans-dioxolane units was investigated. These reactions resulted in "matching" and "mismatching" effects. In the "matched" cases a single diastereoisomer of the corresponding β-amino ester (containing three contiguous stereocentres) is produced. Upon conjugate addition to a homochiral α,β-unsaturated ester containing a cis-dioxolane unit, in the "mismatched" case it is the stereocontrol of the substrate which is dominant over that of the lithium amide, whilst upon addition to homochiral α,β-unsaturated esters containing a trans-dioxolane unit the stereocontrol of the homochiral lithium amide is dominant. Hydrogenolytic N-deprotection of the β-amino ester products of conjugate addition gives access to polyoxygenated β-amino acid derivatives.
Davies, Stephen G.,Durbin, Matthew J.,Goddard, Euan C.,Kelly, Peter M.,Kurosawa, Wataru,Lee, James A.,Nicholson, Rebecca L.,Price, Paul D.,Roberts, Paul M.,Russell, Angela J.,Scott, Philip M.,Smith, Andrew D.
supporting information; experimental part
p. 761 - 776
(2009/06/19)

Synthesis of the potent anticancer agents ottelione A and ottelione B in both racemic and natural optically pure forms
(Chemical Equation Presented) The powerful antitumor agents ottelione A and B were synthesized in racemic form by a method that relies on selective ring closing metathesis. Optically pure natural (+)-ottelione A was then made from D-ribose, via an α-keto cyclopropane. A key feature of the route is that the cyclopropyl group controls the stereochemistry in the attachment of the ArCH2 unit and is then converted by the action of SmI2 into a vinyl group, so that the substituents on the resulting five-membered ring have the required trans relationship. Epimerization of an intermediate gave access by the same method to the trans ring fused isomer (-)-ottelione B.
Clive, Derrick L. J.,Liu, Dazhan
p. 3078 - 3087
(2008/09/19)

Highly (E)-selective wadsworth-emmons reactions promoted by methylmagnesium bromide
(Chemical Equation Presented) An experimentally simple protocol for the very highly (E)-selective Wadsworth-Emmons reaction [(E):(Z) selectivities in excess of 180:1 in some cases] of a range of straight-chain and branched aliphatic, substituted aromatic, and base-sensitive aldehydes via reaction with an alkyl diethylphosphonoacetate and MeMgBr is reported.
Claridge, Timothy D. W.,Davies, Stephen G.,Lee, James A.,Nicholson, Rebecca L.,Roberts, Paul M.,Russell, Angela J.,Smith, Andrew D.,Toms, Steven M.
supporting information; experimental part
p. 5437 - 5440
(2009/06/18)

Studies on oxidopyrylium [5 + 2] cycloadditions: Toward a general synthetic route to the C12-hydroxy daphnetoxins
12-Hydroxydaphnetoxins, members of the structurally fascinating daphnane diterpene family, exhibit a wide range of significant biological activities. A general route to the BC-ring system of 12-hydroxy daphnetoxins is reported based on D-ribose. Depending on the choice of protecting groups and solvent, the oxidopyrylium-alkene [5 + 2] cycloaddition originating from A provides cycloadduct diastereomer B or C with good to excellent selectivity.
Wender, Paul A.,Bi, F. Christopher,Buschmann, Nicole,Gosselin, Francis,Kan, Cindy,Kee, Jung-Min,Ohmura, Hirofumi
p. 5373 - 5376
(2007/10/03)

Bromocyclization of unsaturated oximes. Synthesis of five-membered cyclic nitrones (pyrroline N-oxides)
The cyclization of a ribose-derived pentenose oxime with various halogen electrophiles showed bromine to be the most effective reagent, leading to 80% of L-lyxo/D-ribo-pyrroline N-oxides in an 84:16 diastereomeric ratio. In order to explore the scope of t
Gulla, Mahendra,Bierer, Lars,Schmidt, Stefan,Redcliffe, Leo,J?ger, Volker
p. 471 - 485
(2007/10/03)

A concise synthetic route to the conduritols from pentoses
A short synthetic strategy for preparation of the conduritols is described. The key step employs a zinc-mediated fragmentation of protected methyl 5-deoxy-5-iodo-D-pentofuranosides followed by an allylation of the intermediate aldehyde in the same pot. Th
Keinicke, Lise,Madsen, Robert
p. 4124 - 4128
(2007/10/03)

Synthesis and assignment of absolute configuration of (-)-oleocanthal: A potent, naturally occurring non-steroidal anti-inflammatory and anti-oxidant agent derived from extra virgin olive oils
(Chemical Equation Presented) Effective total syntheses and the assignment of absolute configurations of both the (+)- and (-)-enantiomers of oleocanthal 1 (a.k.a. deacetoxy ligstroside aglycon), the latter derived from extra virgin olive oils and known to be responsible for the back of the throat irritant properties of olive oils, have been achieved. The absolute and relative stereochemistry of the naturally occurring enantiomer (-)-1 proved to be 3S,4E. Both syntheses begin with D-(-)-ribose, proceed in 12 steps, and are achieved with an overall yield of 7%. Both enantiomers proved to be non-steroidal anti-inflammatory and anti-oxidant agents.
Smith III, Amos B.,Han, Qiang,Breslin, Paul A. S.,Beauchamp, Gary K.
p. 5075 - 5078
(2007/10/03)

An improved approach to chiral cyclopentenone building blocks. Total synthesis of pentenomycin I and neplanocin A
An improved approach to enantiomerically pure hydroxylated cyclopentenones is reported here, which involves intramolecular nitrone cycloaddition of sugar-derived chiral pent-4-enals and hex-5-en-ones-2 followed by N-O bond cleavage, quaternization of the amine thus produced, and finally oxidative elimination of the amino group. Synthesis of pentenomycin I and neplanocin A is described following this methodology.
Gallos, John K.,Stathakis, Christos I.,Kotoulas, Stefanos S.,Koumbis, Alexandros E.
p. 6884 - 6890
(2007/10/03)

Preparation of carbocyclic S-adenosylazamethionine accompanied by a practical synthesis of (-)-aristeromycin
For the preparation of a carbocyclic nitrogen analogue of S-adenosylmethionine (carba-AdoazaMet, 4), a practical synthesis of (-)-aristeromycin (7) has been developed using variations of literature procedures. This approach called for a stereospecific synthesis of (3aR,6aR)-2,2-dimethyl-3a, 6a-dihydrocyclopenta[1,3]dioxol-4-one ((4R, 5R)-4,5-O-isopropylidene-2-cyclopentenone) (8), which was achieved by modifying reported procedures from D-(-)-ribose.
Yang, Minmin,Ye, Wei,Schneller, Stewart W.
p. 3993 - 3996
(2007/10/03)

Carbohydrate carbocyclization by a zinc-mediated tandem reaction and ring-closing enyne metathesis
Methyl 5-deoxy-5-iodo-pentofuranosides are reductively ring-opened and propargylated in a tandem fashion in the presence of zinc. The 1,7-enynes thus obtained are subjected to ring-closing enyne metathesis with catalyst B to produce functionalized 1-vinyl cyclohexenes. By adding BnNH2 to the tandem reaction, an amino group can be introduced in the 1,7-enyne products. Addition of 2-TMS-ethynylcerium(III) chloride after the reductive ring-opening produces the corresponding 1,6-enynes. Further annulation of the product 1,3-dienes can be achieved through a Diels - Alder reaction with good control of stereochemistry. These procedures constitute efficient methods for rapid carbocyclization and annulation of carbohydrates to produce a variety of functionalized five- and six-membered ring systems.
Poulsen, Carina Storm,Madsen, Robert
p. 4441 - 4449
(2007/10/03)

Synthesis of polyoxygenated bicyclic systems containing medium-sized rings from carbohydrates via tandem metathesis of dienynes.
[reaction: see text] Highly functionalized (5-7), (5-8), and (6-8) ring systems have been prepared from carbohydrates via tandem ring-closing metathesis of dienynes.
Boyer,Hanna,Ricard
p. 3095 - 3098
(2007/10/03)

A concise synthesis of (-)-endo-brevicomin
A new method for the synthesis of (-)-endo-brevicomin from D-ribose in four steps is reported.
Gallos, John K.,Kyradjoglou, Loukia C.,Koftis, Theocharis V.
p. 781 - 784
(2007/10/03)

Reductive ring opening of 6-deoxy-6-iodopyranosides and 5-deoxy-5-iodofuranosides by manganese. A convenient procedure for the preparation of chiral 5-hexenals and 4-pentenals
Reaction of fully protected 6-iodopyranosides and 5-iodofuranosides with Mn in the presence of trimethylsilyl chloride and PbCl2 (Takai-conditions) afforded the corresponding 5-hexenals and 4-pentenals in good to moderate yields.
Tanaka,Yamano,Mitsunobu
p. 1620 - 1622
(2007/10/03)

Pyrrolidine N-oxides by stereoselective addition of Grignard and lithium compounds to 4,5-dideoxy-2,3-O-isopropylidene-D-erythro-4-pentenose N-benzyl nitrone and subsequent Cope-House cyclization
The addition of Grignard reagents to D-erythro-4-pentenose N-benzyl nitrone 5, which is easily accessible from D-ribose, furnishes ω-unsaturated hydroxylamines that readily undergo Cope-House cyclization to afford pyrrolidine N-oxides. The stereoselectivity of the addition step is altered by either employing organolithium compounds or Lewis acids as complexing agents. The pyrrolidine N-oxides obtained by this sequence serve as key intermediates in the synthesis of 2,5-disubstituted pyrrolidine-3,4-diols (to be discussed in detail separately), both constituting new potential inhibitors of glycosidases.
Palmer, Andreas M.,Jaeger, Volker
p. 1293 - 1308
(2007/10/03)

Synthesis of Hydroxylated Pyrrolizidines Related to Alexine using Cycloaddition Reactions of Functionalized Cyclic Nitrones
Cycloaddition reactions of the functionalized Δ1-pyrroline-N-oxides 10 and 19 have been used to prepare the hydroxylated pyrrolizidines 6 and 7 respectively, which are related to the natural products alexine and australine.
Hall, Adrian,Meldrum, Kevin P.,Therond, Patrick R.,Wightman, Richard H.
p. 123 - 125
(2007/10/03)

Evaluation of D-ribose as an enantiopure building block for construction of the C-ring of taxol and its congeners
The enantiomerically pure Z vinyl iodide 20 is shown to be readily available from D-ribose via a sequence involving zinc-promoted reductive unmasking of an aldehyde and homologation with (iodomethylene)triphenylphosphorane. The vinyl anion produced by halogen-metal exchange adds from the endo direction to an enantiopure ketone prepared from D-camphor. The resulting carbinol undergoes anionic oxy-Cope rearrangement and C-methylation with complete stereocontrol to set the appropriate C-3 stereochemistry of taxol. Dihydroxylation of this intermediate brings about facile transannular hemiketalization. DIBAL-H reduction of this intermediate does not affect the hemiketal, but does reduce the acetonide regiospecifically. An unusual transannular hydride shift occurs during subsequent heating with dibutyltin oxide, as confirmed by X-ray crystallography. When transannular hemiketalization is skirted, hydroboration-oxidation of the side chain leads to an acetaldehyde which is notably prone to β-elimination. Treatment with potassium carbonate in methanol does eventuate in ring closure via an aldol addition reaction, but only after methanol has been added in Michael fashion to the α,β-unsaturated aldehyde.
Paquette,Bailey
p. 7849 - 7856
(2007/10/03)

Synthesis of Enantiomerically Pure Bicyclohexanes from D-Ribose by Intramolecular Cyclopropanation
Highly functionalized optically pure bicyclohexan-2-one 6a and 6b are easily obtained by the intarmolecular cyclopropanation of a D-ribose derivative using the iodonium ylide or diazo compound methods, which afford the final products with opposite diastereoselectivities.
Gallos, John K.,Koftis, Theocharis V.,Koumbis, Alexandros E.
p. 611 - 612
(2007/10/02)

Expeditoious Synthesis of Aminocyclopentitols from D-Ribose via Intramolecular Nitrone Cycloaddition
The synthesis of 4α-aminocyclopentane-1α,2β,3β-triol (a key-intermediate in the preparation of carbocyclic nucleosides) and its N-substituted derivatives, has been achieved by the intarmolecular nitrone cycloadditions of a γ-unsaturated aldehyde, easily accessible from D-ribose, followed by reductive N-O bond cleavage in the resulting bicyclic oxazanes.
Gallos, John K.,Goga, Efthymia G.,Koumbis, Alexandros E.
p. 613 - 614
(2007/10/02)

Substrate Specificity and Carbohydrate Synthesis Using Transketolase
This paper describes the use of the enzyme transketolase as a catalyst in organic synthesis.The properties of transketolase from both yeast and spinach were investigated.The yeast enzyme was found to be more convenient for routine use.Examination of the substrate specificity of yeast tansketolase demonstrated that the enzyme accepts a wide variety of 2-hydroxy aldehydes as substrates.A practical protocol for tansketolase-catalyzed condensation of hydroxypyruvic acid with these aldehydes has been developed and used for the synthesis of four carbohydrates: L-idose, L-gulose, 2-deoxy-L-xylohexose, and L-xylose.
Kobori, Yoshihiro,Myles, David C.,Whitesides, George M.
p. 5899 - 5907
(2007/10/02)