75629-74-2Relevant academic research and scientific papers
Stereoselective synthesis of zooxanthellactone
Jakobsen, Martin Gjerde,Vik, Anders,Hansen, Trond Vidar
supporting information, p. 2842 - 2844 (2014/05/06)
The marine polyunsaturated natural product zooxanthellactone was synthesized in six steps and in 11% overall yield from eicosapentaenoic acid. The key synthetic steps were a Sonogashira cross-coupling reaction and a stereoselective semi-reduction. These efforts, together with NMR and optical rotation data, confirmed the reported structure of zooxanthellactone.
Chirality transfer in an Ireland-Claisen rearrangement: A new approach toward the Iboga alkaloids
Hoeck, Stefan,Koch, Florian,Borschberg, Hans-Juerg
, p. 1801 - 1808 (2007/10/03)
The synthesis of the isoquinuclidine core of the Iboga alkaloid family is described. This building block contains the entire stereochemical information of the targeted natural products. Starting with (S)-4-(hydroxymethyl)-4- butanolide, a derivative available in two steps from L-glutamate, (S)-4-benzyloxy-5,5-dimethoxypentanoic acid was obtained in four steps. Mitsunobu esterification with (S)-but-3-en-2-ol furnished the inverted ester, which was then subjected to an Ireland-Claisen rearrangement. This crucial step took place with a very satisfactory chirality transfer from the alcohol component to the new carbon backbone of the product. After transformation of the resulting silyl ester function into a hydroxylamino group, the dimethyl acetal moiety was hydrolyzed with 3M sulfuric acid at 47°C. Under these conditions, the resulting cyclic nitrone could not be isolated, because it underwent a rapid intramolecular nitrone-olefin [3+2]-cycloaddition reaction to furnish the expected tricyclic isoxazolidine derivative in 67% yield. After chromatographic purification, this product was obtained enantiomerically pure and with a chemical purity of 96%. The targeted isoquinuclidine building block was thus obtained from (S)-4-(hydroxymethyl)-4-butanolide in 13 steps with an overall yield of 9.2%, which amounts to an average yield of 83.3% per step.
Expeditious syntheses of sugar-modified nucleosides and collections thereof exploiting furan-, pyrrole-, and thiophene-based siloxy dienes
Rassu, Gloria,Zanardi, Franca,Battistini, Lucia,Gaetani, Enrico,Casiraghi, Giovanni
, p. 168 - 180 (2007/10/03)
A series of individual sugar-modified pyrimidine nucleosides including enantiomerically enriched 2',3'-dideoxynucleosides 14a-c (α and β anomers of L- and D-series), 2',3'-dideoxy-4'-thionucleosides 21a-c (α and β anomers of L- and D-series), and 2',3'-dideoxy-4'-azanucleosides 28a-c (β anomers of L- and D-series) were synthesized, with uniform chemistry and high stereochemical efficiency, exploiting a triad of versatile heterocyclic siloxy dienes, namely, 2-(tert-butyldimethylsiloxy)furan (TBSOF), 2-(tert- butyldimethylsiloxy)thiophene (TBSOT), and N-(tert-butoxycarbonyl)-2-(tert- butyldimethylsiloxy)pyrrole (TBSOP). The synthetic procedure advantageously used both enantiomers of glyceraldehyde acetonide (D-1 and L-1) as sources of chirality and as synthetic equivalents of the formyl cation. The outlined chemistry also allowed for the rapid assemblage of a 30-member collection of racemic nucleosides (D,L-L) as well as one 15-member ensemble of chiral analogues (L-L), along with some related sublibraries.
MICROBIAL TRANSFORMATION OF (-)-VERNOLIC ACID INTO (4R,5R)-5-HYDROXY-γ-DECALACTONE
Albrecht, Wolfgang,Tressl, Roland
, p. 1391 - 1396 (2007/10/02)
(-)-Vernolic acid, isolated and purified from seeds of Euphorbia lagascae was administered to cultures of Sporobolomyces odorus. (4R,5R)-5-Hydroxy-γ-decalactone 1 accumulated as the main product.The configuration of the product was determined by synthesis of all four stereoisomers and comparison of spectroscopic and chromatographic data.
