99032-03-8Relevant academic research and scientific papers
A Unified Synthetic Approach to Optically Pure Curvularin-Type Metabolites
Allu, Srinivasa Rao,Banne, Sreenivas,Jiang, Jia,Qi, Na,Guo, Jian,He, Yun
, p. 7227 - 7237 (2019/06/07)
A unified and concise approach to the synthesis of nine curvularin-type metabolites and two analogues has been developed with few steps and high yields. Among them, sumalactones A-D were synthesized for the first time. The key steps in this approach inclu
First stereoselective total synthesis of an anti-fouling agent, C2-symmetric natural macrolide trichobotryside A
Narala, Siva Ganesh,Nagalatha,Venkat Narsaiah
, p. 495 - 508 (2019/03/08)
A stereoselective total synthesis of 16-membered macrodiolide trichobotryside A has been accomplished. The key features are: regioselective epoxide opening, Reetz anti-allylation, Sharpless asymmetric epoxidation, cross metathesis and Yamaguchi protocols
Total Synthesis of Tetraketide and Cryptorigidifoliol i via a Sequential Allylation Strategy
Padhi, Birakishore,Reddy, G. Sudhakar,Mohapatra, Debendra K.
, p. 2788 - 2796 (2016/12/06)
A unified and efficient synthetic route for both tetraketide (1) and cryptorigidifoliol I (2) has been devised successfully from commercially available starting materials in 11 and 17 steps, with 16% and 11% overall yields, respectively. Highlights of the syntheses involved sequential Lewis acid-catalyzed highly regio- and diastereoselective allylations and intramolecular Mitsunobu lactonization.
Intramolecular OH...Fluorine Hydrogen Bonding in Saturated, Acyclic Fluorohydrins: The γ-Fluoropropanol Motif
Linclau, Bruno,Peron, Florent,Bogdan, Elena,Wells, Neil,Wang, Zhong,Compain, Guillaume,Fontenelle, Clement Q.,Galland, Nicolas,Le Questel, Jean-Yves,Graton, Jér?me
, p. 17808 - 17816 (2015/12/08)
Fluorination is commonly exercised in compound property optimization. However, the influence of fluorination on hydrogen-bond (HB) properties of adjacent functional groups, as well as the HB-accepting capacity of fluorine itself, is still not completely understood. Although the formation of OH...F intramolecular HBs (IMHBs) has been established for conformationally restricted fluorohydrins, such interaction in flexible compounds remained questionable. Herein is demonstrated for the first time - and in contrast to earlier reports - the occurrence of OH...F IMHBs in acyclic saturated γ-fluorohydrins, even for the parent 3-fluoropropan-1-ol. The relative stereochemistry is shown to have a crucial influence on the corresponding h1JOH...F values, as illustrated by syn- and anti-4-fluoropentan-2-ol (6.6 and 1.9 Hz). The magnitude of OH...F IMHBs and their strong dependence on the overall molecular conformational profile, fluorination motif, and alkyl substitution level, is rationalized by quantum chemical calculations. For a given alkyl chain, the "rule of shielding" applies to OH...F IMHB energies. Surprisingly, the predicted OH...F IMHB energies are only moderately weaker than these of the corresponding OH...OMe. These results provide new insights of the impact of fluorination of aliphatic alcohols, with attractive perspectives for rational drug design.
Palladium-catalyzed selective anti-markovnikov oxidation of allylic esters
Dong, Jia Jia,Fananas-Mastral, Martin,Alsters, Paul L.,Browne, Wesley R.,Feringa, Ben L.
, p. 5561 - 5565 (2013/06/27)
An aldol alternative: The palladium(II)-catalyzed anti-Markovnikov oxidation of allylic esters to aldehydes at room temperature provides a viable alternative to valuable cross aldol products. High regioselectivity towards the aldehyde product was achieved using the ester protecting group for the allylic alcohol. Rapid isomerization and the much higher rate of oxidation of the branched isomer result in the same product forming from both linear and branched allylic esters. Copyright
Lewis acid-promoted addition of 1,3-bis(silyl)propenes to aldehydes: A route to 1,3-dienes
Borg, Tessie,Tuzina, Pavel,Somfai, Peter
, p. 8070 - 8075 (2011/11/28)
The Lewis acid-promoted addition of 1,3-bis(silyl)-propenes to aldehydes to provide the corresponding (E)-1,3-dienes in excellent stereoselectivity and good to excellent yields is reported. The procedure is mild, base-free, and operationally straightforward.
Stereospecific total synthesis of (-)-8-epi-hyperaspine
Ma, Dawei,Zhu, Wei
, p. 8609 - 8612 (2007/10/03)
Condensation of protected δ-hydroxy-β-amino ester 7 with a β-keto ester provides vinylogous urethane 8, which is cyclized under the action of t-BuOK followed by decarboxylation to afford enone 12. Hydrogenation of 12 or its N,O-diprotected derivative 13 g
Synthesis of chiral 4-hydroxy-2,3-unsaturated carbonyl compounds from 3,4-epoxy alcohols by oxidation: Application in the formal synthesis of macrosphelide A
Chakraborty, Tushar K.,Purkait, Subhas,Das, Sanjib
, p. 9127 - 9135 (2007/10/03)
An interesting transformation during the oxidation of 3,4-epoxy alcohols 1a-d, derived from the corresponding homoallylic alcohols, led to the formation of 4-hydroxy-2,3-unsaturated carbonyls 2a-d in very good yields. One of these products 2c was transfor
Synthetic Studies toward the Total Synthesis of Swinholide. 1. Stereoselective Construction of the C19-C35 Subunit
Keck, Gary E.,Lundquist, Gregory D.
, p. 4482 - 4491 (2007/10/03)
The development of an approach directed at the total synthesis of the complex cytotoxic marine macrodiolide swinholide is described. The present study focuses on the development of a synthetic route for the preparation of the C19-C35 segment of the structure, which is composed of a trisubstituted pyran moiety with a contrathermodynamic anti arrangement of the C2 and C6 pyran substituents (swinholide C27 and C31) which is joined by an ethano linker to an acyclic array containing five contiguous stereocenters. The pyran subunit was constructed using a stereoselective allylation of a β-alkoxy aldehyde with 1,3-asymmetric induction and a second stereoselective allylation to prepare the C-glycosidic type of linkage. Use of the Hafner-Duthaler reagent was investigated as a potential means of constructing the anti vicinal hydroxyl-methyl relationships found in the C19-C24 segment but was found not to be practical in this instance. The Evans bis propionate methodology was used to introduce a four-carbon unit, and a Mukaiyama aldol was used for chain extension to incorporate the remaining two carbons and two stereocenters of this segment. Attempted use of the Hanessian benzylidene acetal fragmentation reaction in this sequence was thwarted by neighboring group participation of an oxazolidinone in one case and an unexpected regiochemical outcome in another. The approach developed affords the C19-C35 substructure in 18 steps overall from ethyl acetoacetate and in adequate quantities (10% overall yield) to support the projected total synthesis.
Die Struktur von Maitotoxin - I: Konfiguration der C1-C14-Seitenkette
Sasaki, Makoto,Matsumori, Nobuaki,Maruyama, Takahiro,Nonomura, Taro,Murata, Michio,et al.
, p. 1782 - 1785 (2007/10/03)
Keywords: Konfigurationsbestimmung; Konformation; Maitotoxin; Naturstoffe; NMR-Spektroskopie
