- Four Stereoisomers of 2-Aminomethyl-1-cyclopropanecarboxylic Acid: Synthesis and biological evaluation
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Here, we report a practical method for asymmetric synthesis of cyclopropane-fused GABA analogs. Starting from 2-furaldehyde, the cis-isomer (CAMP) was synthesized over 10 steps; (1)- and (+)-CAMP¢HCl were synthesized by employing d- and l-menth
- Oikawa, Masato,Sugeno, Yuka,Tukada, Hideyuki,Takasaki, Yuichi,Takamizawa, Satoshi,Irie, Raku
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supporting information
p. 1816 - 1823
(2019/11/13)
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- Catalysis-based and protecting-group-free total syntheses of the marine oxylipins hybridalactone and the ecklonialactones A, B, and C
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Concise and protecting-group-free total syntheses of the marine oxylipins hybridalactone (1) and three members of the ecklonialactone family (2-4) were developed. They deliver these targets in optically pure form in 14 or 13 steps, respectively, in the longest linear sequence; five of these steps are metal-catalyzed and four others are metal-mediated. The route to either 1 or 2-4 diverges from the common building block 22, which is accessible in 7 steps from 2[5H]furanone by recourse to a rhodium-catalyzed asymmetric 1,4-addition reaction controlled by the carvone-derived diene ligand 35 and a ring-closing alkene metathesis (RCM) catalyzed by the ruthenium indenylidene complex 17 as the key operations. Alternatively, 22 can be made in 10 steps from furfural via a diastereoselective three-component coupling process. The further elaboration of 22 into hybridalactone as the structurally most complex target with seven contiguous chiral centers was based upon a sequence of cyclopropanation followed by a vanadium-catalyzed epoxidation, both of which were directed by the same free hydroxy group at C15. The macrocyclic scaffold was annulated to the headgroup by means of a ring-closing alkyne metathesis reaction (RCAM). In response to the unusually high propensity of the oxirane of the targeted oxylipins for ring opening, this transformation had to be performed with complexes of the type [(Ar3SiO)4Mo≡CPh] [K·OEt2] (43), which represent a new generation of exceedingly tolerant yet remarkably efficient catalysts. Their ancillary triarylsilanolate ligands temper the Lewis acidity of the molybdenum center but are not sufficiently nucleophilic to engage in the opening of the fragile epoxide ring. A final semireduction of the cycloalkyne formed in the RCAM step to the required (Z)-alkene completed the total synthesis of (-)-1. The fact that the route from the common fragment 22 to the ecklonialactones could follow a similar logic showcased the flexibility inherent to the chosen approach.
- Hickmann, Volker,Kondoh, Azusa,Gabor, Barbara,Alcarazo, Manuel,Fuerstner, Alois
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scheme or table
p. 13471 - 13480
(2011/10/10)
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- Highly enantioselective synthesis and potential biological activity of chiral novel nucleoside analogues containing adenine and naturally phenol derivatives
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This paper described an efficient synthetic strategy for chiral acyclic nucleoside analogues containing both the phenoxy components of some bioactive natural compounds and a heterocyclic base. The phenoxy components with adenine moiety were incorporated into the chiral acyclic nucleoside analogues through two key synthetic tactics. Chiron 5-(R)-menthyloxy-2(5H)-furanone 5 was obtained in good yield from the cheap starting material furfural via a valuable synthetic route. The asymmetric Michael addition of 5 with adenine and the subsequent reduction reaction afforded the key chiral intermediate, 2-(R)-(9′-adeninyl)-1,4-butanediol 8. The absolute configuration of 8 was established by X-ray crystallography. The intermolecular dehydration reaction between 2-(9′-adeninyl)-1,4-butanediol 8 and phenoxy components 9 on treatment with diethyl azodicarboxylate and triphenylphosphine was carried out to give the chiral acyclic nucleoside analogues 1a-1e. The regioselectivity of the reaction was established by NMR methods, especially through 13C NMR shifts and NOE effect observed in the target molecule 1c, as well as by HMBC/HMQC experiments. The target compounds were tested for inhibition of cytopathogenicity against different cancer cells and exhibited potential anticancer activity.
- He, Lan,Liu, Yumei,Zhang, Wei,Li, Ming,Chen, Qinghua
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p. 8505 - 8511
(2007/10/03)
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- Origin of Chiral Induction in Radical Reactions with the Diastereoisomers (5R)- and (5S)-5-l-Menthyloxyfuran-2[5H]-one
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Acetalization of 5-hydroxyfuran-2[5H]-one with l-menthol yields (5R)-(1) and (5S)-5-l-menthyloxyfuran-2[5H]-one (2) in equal amounts. The diastereomer 1 crystallizes preferentially. For the first time, the isolation of pure diastereoisomer 2 is reported. Different diastereoselectivities were observed in the radical tandem reaction of 1 and 2 with N,N-dimethylaniline. The privileged conformations in solution of the substrates and the products of the radical reaction were then determined, and X-ray crystal structure analyses were carried out on the reaction products. The different stereoselectivities in both cases are explained by different orientations of the menthyloxy substituent.
- Marinkovic, Sinisa,Brule, Cedric,Hoffmann, Norbert,Prost, Elise,Nuzillard, Jean-Marc,Bulach, Veronique
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p. 1646 - 1651
(2007/10/03)
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- Method for preparing (+)-biotine
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The invention relates to a novel method for preparing biotine while using 5-hydroxy-2(5H)-furanone as a starting substance. The invention also relates to a method in which 1-chlorosulfonyl-1,2,2a,3,5,5a-hexa-hydro-3-((1R)-menthyloxy-)-furo[3,4-b]azet-2-on
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- A valuable synthetic route to spiro-cyclopropane derivatives containing multiple stereogenic centers
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The unusual, functionalized spiro-cyclopropane derivatives containing four stereogenic centers 8a-8f were obtained in good yields with d.e. ≥98% via tandem double Michael addition/internal nucleophilic substitution of the novel chiral synthon, 5-l-menthyl
- Huang, Hui,Chen, Qinghua
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p. 1295 - 1307
(2007/10/03)
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- Synthesis of enantiomerically pure spiro-cyclopropane derivatives containing multichiral centers
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A novel chiral source, 5-(R)-[(1R,2S,5R)-(-)-menthyloxy]-3-bromo-2(5H)- furanone (5a), was obtained in 46% yield with d.e.≥98% from the epimeric mixture of 5-(1-menthyloxy)-3-bromo-2(5H)-furanone (Sa+5b) obtained via the bromination of an epimeric mixture
- Huang, Hui,Chen, Qinghua
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p. 4103 - 4107
(2007/10/03)
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- Studies on the chemistry of the chiral nitronic acid and nitronic esters
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Some new chemistry of the chiral nitronic acid and nitronic esters is described. Conversions with retention of configuration are found among the chiral nitronic acid, oxime, nitronic esters and O-alkyloximes. α,β- Elimination reactions of nitronic esters are observed for the first time. Novel and enantiopure chiral bisheterocyclic compounds are obtained via highly diastereoselective 1,3-dipolar cycloaddition of the chiral nitronic esters with ethyl acrylate.
- Kang, Fu-An,Yin, Cheng-Lie
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p. 3585 - 3589
(2007/10/03)
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- Enantioselective synthesis of (R)- and (S)-2-alkyl-1,4-butanediols via enantiomerically pure 3-alkyl-5-(menthyloxy)butyrolactones
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A general and practical synthesis of optically pure (R)- and (S)-2-ethyl, 2-propyl and 2-isopropyl-1,4-butanediols, 9a-c, has been accomplished from optically pure 5-(menthyloxy)butenolides in five steps in good yields.
- Lee, Namkyu,Kim, Young-Woo,Chang, Kieyoung,Kim, Key H.,Jew, Sang-Sup,Kim, Dae-Kee
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p. 2429 - 2432
(2007/10/03)
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- Stereospecific radical addition of isopropanol and n-butanal to (5R)-(l-menthyloxy)furan-2(5H)-one
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The radical addition of PriOH and n-butanal to (5R)-5-(l-menthyloxy)furan-2(5H)-one occurs regio- and diastereospecifically at position 4 of the furanone ring. - Keywords: diastereoselectivity, regioselectivity, radical addition, (5R)-5-(l-menthyloxy)furan-2(5H)-one, 2-propanol, n-butanal, (1)H, (13)C NMR spectra
- Belokon', Yu. N.,Kochetkov, K. A.,Moskalenko, M. A.,Raevsky, N. I.,Savel'eva, T. F.,et al.
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p. 517 - 519
(2007/10/02)
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- Asymmetric Synthesis of Dibenzylbutyrolactones and Aryltetralin Lignan Lactones by Tandem Cojugate Addition to a Chiral Butenolide
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Addition of sulfur-stabilised carbanions to (-)-5-(1-menthyloxy)furan-2(5H)-one followed by reaction with an aromatic aldehyde affords a short synthesis of enantiomerically pure dibenzylbutyrolactone derivatives.Desulfurisation with NaBH4/NiCl2 proceeds in almost quantitative yield, and reduction with NaBH4/KOH gives the parent dibenzylbutyrolactones including (-)-6-epi-podorhizol.These undergo cyclisation with acid to give homochiral aryltetralines including (-)-deoxyisopodophyllotoxin in high yield.
- Pelter, Andrew,Ward, Robert S.,Jones, D. Martin,Maddocks, Peter
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p. 2621 - 2630
(2007/10/02)
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- Asymmetric Diels-Alder Reactions with 5-Menthyloxy-2(5H)-furanone
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A new class of chiral dienophiles, 5-alkoxy-2(5H)-furanones, has been developed.Both enantiomers of 5-menthyloxy-2(5H)-furanone are readily available in enantiomerically pure form, starting from furfural and d- or l-menthol.Excellent diastereoselectivities (d.e. 99percent) are obtained in thermal Diels-Alder reactions with several cyclic and acyclic dienes.The use of silyl dienol ethers has resulted in new routes to enantiomerically pure cyclohexanones in a highly regioselective manner.
- Jong, Johannes C. de,Bolhuis, Fre van,Feringa, Ben L.
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p. 1247 - 1262
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF HOMOCHIRAL DIBENZYLBUTYROLACTONE LIGNANS BY CONJUGATE ADDITION TO A CHIRAL BUTENOLIDE
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Addition of sulphur stabilised carbanions to a chiral non-racemic butenolide followed by reaction with an aromatic aldehyde affords a short synthesis of homochiral dibenzylbutyrolactone derivatives.Desulphurisation of the first formed adducts proceeds in almost quantitative yield to afford the parent lignan.
- Pelter, Andrew,Ward, Robert S.,Jones, D. Martin,Maddocks, Peter
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p. 857 - 860
(2007/10/02)
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- CHIRAL INDUCTION IN PHOTOCHEMICAL REACTIONS-XII. SYNTHESIS OF CHIRAL CYCLOBUTANE DERIVATIVES FROM (+)-5-MENTHYLOXY-2--FURANONE AND ETHYLENE
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The temperature dependence of the diastereoselectivity in the photochemical -cycloaddition of (+)-5-menthyloxy-2--furanone to ethylene is investigated and the preparative isolation of the pure (1R,4S,5S)- as well as (1S,4S,5R)-4-(+)-menthyloxy-3-oxa-2-oxobicyclo-heptane is described.
- Hoffmann, Norbert,Scharf, Hans-Dieter,Runsink, Jan
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p. 2637 - 2638
(2007/10/02)
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- ASYMMETRIC 1,4-ADDITIONS TO 5-ALKOXY-2(5H)-FURANONES. AN EFFICIENT SYNTHESIS OF (R)- AND (S)-3,4-EPOXY-1-BUTANOL
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The synthesis of enantiomerically pure 5-menthyloxy-2(5H)-furanones is described as well as the diastereoselective 1,4-addition of thiols to these butenolides to yield new homochiral C4-synthons.Kinetic resolution of 5-methoxy-2(5H)-furanone, with an enantiomeric excess of 13percent, was achieved by cinchonidine catalysed thiophenol addition. The synthetic utility of the asymmetric thiol additions is illustrated in an efficient route to enantiomerically pure (R)- and (S)-3,4-epoxy-1-butanol.
- Feringa, Ben L.,Lange, Ben De
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p. 7213 - 7222
(2007/10/02)
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- Asymmetric Diels-Alder Reactions with a Chiral Maleic Anhydride Analogue 5-(1-Menthyloxy)-2(5H)-furanone
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5-(1-Menthyloxy)-2(5H)-furanone was used as a chiral dienophile in thermal asymmetric Diels-Alder reactions with several cyclic and acyclic dienes to give enantiomerically pure products.
- Feringa, Ben L.,Jong, Johannes C. de
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p. 1125 - 1127
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF 2-AMINO-1,4-DIOLS
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Diastereoselective addition of amines to (l)-5-menthyloxy-2-(5H)-furanone yields aminolactones that upon reduction with LiAlH4 provide enantiomerically pure aminodiols.
- Feringa, Ben L.,Lange, B. de
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p. 1303 - 1306
(2007/10/02)
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