- Chiron Approaches to the Antitumor Natural Product Fuzanin D
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Fuzanin D, a pyridine-containing natural product, which exhibits cytotoxic activity against DLD-1 cells, is synthesized in a concise manner using l-arabinose or ethyl l-lactate as chiral pool substrates in nine steps (14.4% overall yield) and six steps (30.8% overall yield), respectively. The key steps involve Wittig olefination and olefin cross--metathesis.
- Gao, Yangguang,Cao, Zhou,Su, Chengzhong,Chen, Zefeng,He, Xianran,Ding, Fei,Li, Hang,Zhang, Yongmin
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- 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
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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
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- 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
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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
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- A concise synthesis of the dihydroxy styryllactone, 7-epi-goniodiol
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A short and efficient stereoselective synthesis of dihydroxy styryllactone 7-epi-goniodiol has been achieved in nine steps and 20% overall yield, starting from readily available L-erythrose monoacetonide. The key steps of the synthesis involved a stereoco
- Zeng, PingLi,Wang, Dong,Zhou, Junhui,Dong, Zhibing
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- Preparation of anti -vicinal amino alcohols: Asymmetric synthesis of d - Erythro -sphinganine, (+)-spisulosine, and d - Ribo -phytosphingosine
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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
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- 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
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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.
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- Total synthesis of (+)-cladospolide A
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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
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- A natural ɑ - glucosidase inhibitor Penasulfate A synthetic method (by machine translation)
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The invention provides a natural ɑ - glucosidase inhibitor Penasulfate A synthetic method, including by the 1, 12 - dodecanediol via 5 step synthesis 12 - thirteen carbon olefine acid, L - arabinose via the 3 step synthesis (2 S, 3 R) - 2, 3 - oxygen - isopropyl - 4 - pentene - 1, 2, 3 - triol, (S)- Roche ester via the 8 step synthesis of chiral methyl undecenyl fundamental frequency that mellow boron ester, 12 - thirteen alkenylene acid and (2 S, 3 R) - 2, 3 - oxygen - isopropyl - 4 - pentene - 1, 2, 3 - triol in GrubbsII catalyst under the action of the olefin metathesis reaction, and then with the (R)- piperidine - 2 - carboxylic acid methyl ester reaction to prepare amide, re-oxidation results in the aldehyde, Takai alkene alkylation by thirteen alkenylene iodide, with the insecticidal compositions of the fundamental frequency that chiral methyl mellow boron ester in Pd (PPh3 )4 Catalytic, ethyl alcohol thallium as alkali under the condition of the key Suzuki coupling, hydrogenation reduction, [...], sulfuric acid ester, shall Penasulfate A. The present invention provides natural product Penasulfate A throughout the synthetic route for the first time, the olefin metathesis reactions and Suzuki coupling as a key reaction, the line is comparatively simple high efficiency, a high degree of convergence, the operation is easy to grasp. (by machine translation)
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Paragraph 0029; 0038; 0039
(2019/02/04)
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- D-erythro-sphingosine synthesis method
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The invention relates to a D-erythro-sphingosine synthesis method, comprising the steps of dissolving a compound 6 into dry tetrahydrofuran, adding lithium aluminum hydride under protection of nitrogen, after complete reaction of a raw material, adding a potassium sodium tartrate solution and finishing; extracting through ethyl acetate, concentrating and performing column chromatography; separating to obtain D-erythro-sphingosine. Compared with a traditional method, the synthesis method provided by the invention has the advantages that the use of a large amount of strong base phenyl lithium in a Wittig reaction process is avoided, meanwhile, the yield is increased; an azidation reaction adopts a two-step method of iodination and then azidation, and low temperature reaction in the existing technical scheme is not needed, so that the operation is more convenient and simple.
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Paragraph 0016; 0017; 0022; 0033; 0034
(2017/08/31)
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- First asymmetric total synthesis of aspergillide D
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The first asymmetric total synthesis of a 16-membered macrolide, aspergillide D, is described. The chiral centers of the acid are derived from d-ribose and the alcohol subunit from 1,8-octane diol through Sharpless kinetic resolution, respectively. The other key reactions include Yamaguchi esterification, ring-closing metathesis reaction, and Shiina macrolactonization to construct the fully functionalized macrocycle.
- Jena, Bighnanshu K.,Reddy, G. Sudhakar,Mohapatra, Debendra K.
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supporting information
p. 1863 - 1871
(2017/03/09)
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- 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
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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.
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p. 534 - 546
(2014/05/06)
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- 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
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"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.
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p. 6186 - 6200
(2012/09/05)
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- Application of L-erythrose-derived nitrones in the synthesis of polyhydroxylated compounds via 3,6-dihydro-2H-1,2-oxazine derivatives
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Enantiopure 3,6-dihydro-2H-1,2-oxazines were prepared by [3+3] cyclisations starting from lithiated methoxyallene and the L-erythrose-derived nitrones 1' and 3. The role of the side-chain protective group, which steers the highly selective formation of either anti- or syn-configured products, was demonstrated. A hydroboration/oxidation protocol smoothly converted 1,2-oxazine derivative syn-5 into secondary alcohol 6. After deprotection, polyhydroxylated tetrahydro-2H-1,2-oxazine 11, which can be regarded as an azasugar, was isolated. Analogous treatment of 1,2-oxazine anti-5 with the borane not only provided the expected secondary alcohol 7, but it also induced reduction of the C=C bond and ring opening. Treatment of syn-5 and anti-2 with hydrochloric acid in methanol induced deprotections and cyclisations leading to bicyclic tetrahydro-2H-1,2-oxazine derivatives. The second ring can be either a furan or a pyran ring. In the syn series, furan derivative 12 was formed exclusively, and its hydrogenolysis led to enantiopure aminofuran derivative 14. Acid-promoted rearrangement of unprotected anti-2 led to a mixture of bicyclic compounds with furan or pyran rings fused to the 1,2-oxazine core. However, when TBDPS-protected compound 20 was used it cleanly led to 1,2-oxazine 21 with a fused furan ring and then to aminofuran 22. Alternatively, the N-O bond in unprotected anti-2 was chemoselectively reduced with samarium diiodide, efficiently generating highly functionalized allylic alcohol 23. Acid-promoted cyclisation and deprotection furnished furan derivative 24. Mechanistic suggestions to explain the different outcomes of the acid-induced transformations are provided. Overall, it is demonstrated that the stereodivergent addition of lithiated alkoxyallenes to L-erythrose-derived nitrones allow flexible access to a series of enantiopure amino polyols, including aminofuran derivatives. Copyright
- Jasinski, Marcin,Lentz, Dieter,Moreno-Clavijo, Elena,Reissig, Hans-Ulrich
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scheme or table
p. 3304 - 3316
(2012/08/08)
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- Synthesis of a branched chain aza-C-disaccharide via the cycloaddition of a chiral nitrone to an alkene, both sugar derivatives
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A multistep synthesis of a protected aza-C-disaccharide derivative with a pyrrolidine ring as the azasugar component is described. The key step is a stereoselective cycloaddition reaction of a chiral nitrone derived from D-ribose and a sugar alkene derived from D-galactose. An intramolecular N-alkylation followed by a reductive cleavage of the isoxazolidine N-O bond, in one pot, gave the final product.
- Argyropoulos, Nikolaos G.,Sarli, Vassiliki C.
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p. 4237 - 4240
(2007/10/03)
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- Substrate analogs for the investigation of deoxyxylulose 5-phosphate reductoisomerase inhibition: Synthesis and evaluation
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Deoxyxylulose 5-phosphate (DXP) analogs were synthesized and evaluated as alternative substrates and inhibitors of recombinant Synechocystis PCC6803 DXP reductoisomerase (DXR; EC 1.1.1.267). Five of the compounds tested (1,2-dideoxy-d-threo-3-hexulose 6-phosphate, 1-deoxy-l-ribulose 5-phosphate, 2S,3R-dihydroxybutyramide 4-phosphate, 4S-hydroxypentan-2-one 5-phosphate, and 3S-hydroxypentan-2-one 5-phosphate) acted as relatively weak competitive inhibitors when compared to fosmidomycin. A sixth compound, 3R,4S-dihydroxy-5- oxohexylphosphonic acid, served as an alternate substrate, as has recently been reported for the same compound with Escherichia coli DXR.
- Phaosiri, Chanokporn,Proteau, Philip J.
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p. 5309 - 5312
(2007/10/03)
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- An unusual acetonide group migration
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Treatment of (2S,3R)-2,3-O-isopropyliden-4-penten-1,2,3-triol mesylate with uracil, K2CO3 did not provide the product of S N2 displacement, but an interesting acetonide group migration product 8. The structure of 8 was secured by spectral analysis and single crystal X-ray analysis. The desired product 2 could be ultimately obtained by Mitsunobu reaction of the alcohol 6 with 3-N-benzoyl uracil followed by basic hydrolysis.
- Saksena, Anil K.,Girijavallabhan, Viyyoor M.,Puar, Mohindar S.,Pramanik, Birendra N.,Das, Pradip R.,McPhail, Andrew T.
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p. 7201 - 7204
(2007/10/03)
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- Ultrasound-accelerated synthesis of chiral allylic alcohols promoted by indium metal
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The 2-iodomethyl-O-isopropylidine acetals undergo smoothly β-elimination by indium metal in methanol under sonication to afford the corresponding allylic alcohols in excellent yields with high selectivity. This method tolerates both acid and base labile functional and protecting groups and also free hydroxyl groups present in the molecule. Improved yields and enhanced rates are the remarkable features obtained by ultrasound.
- Yadav,Reddy,Srinivasa Reddy
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p. 5333 - 5336
(2007/10/03)
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- A de novo synthesis of ethyl 2-deoxy-L-ribosides
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A short (7-step) and efficient synthesis of several derivatives of 2- deoxy-L-ribose 1, e.g., the ethyl ribosides, 2abc, has been accomplished from achiral precursors.
- Jung, Michael E.,Nichols, Christopher J.
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p. 4615 - 4618
(2007/10/03)
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- D-Erythronolactone and 2,3-O-Isopropylidene-L-erythrose as C4 Building Units: An Efficient Synthesis of both Enantiomers of endo-Brevicomin and its 7-Vinyl Analogues
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Both enantiomers of endo-brevicomin (+)- and (-)-3a were synthesized from D-erythronolactone (1) and 2,3-O-isopropylidene-L-erythrose (2), respectively.In the course of the synthesis also the 7-vinyl analogues (+)- and (-)-3b of endo-brevicomin are available.The key step of the synthesis is the diastereoselective acetalization of the diols 1 and 10 with 4-(phenylsulfonyl)-2-butanone (4) and boron trifluoride-diethyl ether complex as a catalyst.The described procedure yields the key compounds 5a and ent-7b in good yields and with high diastereomeric purity. - Key Words: Brevicomin / Erythronolactone / Acetalization, diastereoselective / Erythrose, 2,3-O-isopropylidene- / Pheromones
- Gypser, Andreas,Flasche, Michael,Scharf, Hans-Dieter
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p. 775 - 780
(2007/10/02)
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- Synthesis of Optically Active Olefinic Building Blocks from D-Ribonolactone: Isopropylidene Derivatives of D-erythro-Pentenediol and -triol (cis-4-Substituted 5-Vinyldioxolanes)
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Optically active D-erythro-pentenediol and triol acetonides 4-11 were prepared from D-ribonolactone 1, via the acid 4 and the alcohol 9 as key intermediates.Acetonides 4-11 are cis-4-substituted 5-vinyldioxolanes, both needed as standard model substrates
- Jaeger, Volker,Haefele, Brigitte
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p. 801 - 806
(2007/10/02)
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