152840-34-1Relevant academic research and scientific papers
Structural establishment of polygalatenosides A and B by total synthesis
Huang, Chih-Ming,Liu, Rai-Shung,Wu, Tian-Shung,Cheng, Wei-Chieh
, p. 2895 - 2898 (2008/09/21)
The first total synthesis of polygalatenosides A (1) and B (2), originally isolated from the traditional Chinese medicine and reported as antidepressant agents, is described here. Glycosylation between thiogalactosyl donors 6 and 7 and 1-deoxyglucosyl acc
Samarium diiodide-mediated reductive coupling of epoxides and carbonyl compounds: A stereocontrolled synthesis of C-glycosides from 1,2-anhydro sugars
Chiara, Jose Luis,Sesmilo, Esther
, p. 3242 - 3246 (2007/10/03)
Sugar mimics: 1,2-anhydro sugars can be cross-coupled with aldehydes and ketones under very mild conditions and using a wide range of protecting groups to give C-glycosides in good yield in a radical reaction mediated by SmI2 (see scheme; A = n
Preparation of α-C-Glycosides from Glycals
Parrish,Daniel Little
, p. 1439 - 1442 (2007/10/03)
(matrix presented) A novel approach to simple C-glycosides is reported. Reductive ring opening of 1,2-anhydro sugars with titanocene(III) chloride produces an anomeric radical that can be trapped with a variety of agents. The reaction stereospecifically a
Stereospecific synthesis of α- and β-C-glycosides from glycosyl sulfoxides: Scope and limitations
Carpintero,Nieto,Fernandez-Mayoralas
, p. 1768 - 1774 (2007/10/03)
C-Glycosides derived from α-L-fuco-, α-D-gluco-, β-D-gluco-, and α-D-mannopyranose have been synthesized from the corresponding glycosyl phenyl sulfoxide through phenylsulfinyl-lithium exchange, to generate an anomeric carbanion, and subsequent reaction with a carbon electrophile. The reactions were stereospecific and proceeded with retention of the configuration at the anomeric center. Improved yields of C-glycosides were obtained by an inverse addition protocol. Trapping of the anomeric carbanion with aldehydes gave best results. Reaction with ketones, chloroformates, nitriles, and alkyl halides was also explored. Mechanistic aspects of the reaction are discussed.
Synthesis of the C-glycosidic analogue of adenophostin A and its uracil congener as potential IP3 receptor ligands. Stereoselective construction of the C-glycosidic structure by a temporary silicon-tethered radical coupling reaction
Abe, Hiroshi,Shuto, Satoshi,Matsuda, Akira
, p. 4315 - 4325 (2007/10/03)
Synthesis of the C-glycosidic analogue 9 of adenophostin A, a very potent IP3 receptor agonist, and its uracil congener 10 was achieved via a temporary silicon-tethered radical coupling reaction as the key step. Phenyl 3,4,6-tri-O-(p-methoxyben
Hydride addition to 1,2-anhydrosugars: A highly stereoselective route to anhydroalditols
Flaherty, Terrence M.,Gervay, Jacquelyn
, p. 961 - 964 (2007/10/03)
Stereoselective hydride addition to endocyclic 1,2-anhydrosugars has been achieved providing an efficient route to differentially protected anhydroalditols.
Eine hoch stereoselektive Synthese von 1,2-trans-C-Glycosiden ueber Glycosylsamarium(III)-Verbindungen
Mazeas, Daniel,Skrydstrup, Troels,Beau, Jean-Marie
, p. 990 - 993 (2007/10/02)
Stichworte: Aldehyde * Asymmetrische Synthesen * C-Glycoside * Ketone * Samariumverbindungen
Preparation and transmetallation of a triphenylstannyl β-D-glucopyranoside: A highly stereoselective route to β-D-C-glycosides via glycosyl dianions
Frey,Hoffmann,Wittmann,Kessler,Uhlmann,Vasella
, p. 2060 - 2069 (2007/10/02)
The triphenylstannyl β-D-glucopyranoside 4 was synthesized in one step from the 1,2-anhydro-α-D-glucopyranose 3 with (triphenylstannyl)lithium. Transmetallation of 4 with excess BuLi, followed by quenching the dianion 7 with CD3OD gave (IS)-1,5-anhydro-3,4,6-tri-o-benzyl-[1-2H]-D-glucitol (8) in 81% yield. Trapping of 7 with benzaldehyde, isobutyraldehyde, or acroleine gave the expected β-D-configurated products 11, 12, and 13 in good yields. Preparation of C-acyl glycosides from acid chlorides, such as acetyl or benzoyl chloride was not practicable, but addition of benzonitrile to 7 yielded 84% of the benzoylated product 14. Treatment of 7 with MeI led to 15 (30%) along with 40% of 18, C-alkylation being accompanied by halogen-metal exchange. Prior addition of lithium 2-thienylcyanocuprate increased the yield of 15 to 50% and using dimethyl sulfate instead of MeI led to 77% of 15. No α-D-anomers could be detected, except with allyl bromide as the electrophile, which yielded in a 1:1 mixture of the anomers 16 and 17.
SmI2-promoted chemistry at the anomeric center of carbohydrates. Reductive formation and reaction of glycosyl samarium (III) reagents
Pouilly, P. de,Chenede, A.,Mallet, J.-M.,Sinay, P.
, p. 256 - 265 (2007/10/02)
Reaction of 3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexopyranosyl chloride at room temperature with the efficient single electron transfer system of SmI2-THF-HMPA, in the presence of cyclopentanone (Barbier conditions) gave selectively the corresponding α-C-glycoside in 70percent yield.It is postulated that the reactive transient intermediate is a chiral anomeric organosamarium (III) species.Lower yields were obtained in the presence of aldehydes, such as n-butanal or isobutanal.It is also demonstrated that glycosyl phenyl sulfones undergo reductive samariation. 2,3,4,6-Tetra-O-benzyl-β-D-glucopyranosyl phenyl sulfone reacted with cyclopentanone, in the presence of SmI2-THF-HMPA, to give the corresponding β-C-glycoside selectively in 25percent yield, together with the elimination product (40percent).When the protecting group at C-2 was an acetate, a very fast β-elimination of the organosamarium intermediate occurred to give a practically quantitative yield of a substituted glycal.This work constitutes the first application of samarium(II) iodide to the reductive metallation of the anomeric center of carbohydrates.Key words: samarium diiodide / sulfones / carbohydrates / glycals / C-glycosides
