74708-02-4Relevant academic research and scientific papers
A convenient and efficient synthesis of glycals by zinc nanoparticles
Xu, Yun,Wang, Wenjun,Cai, Yu,Yang, Xia,Wang, Peng George,Zhao, Wei
, p. 46662 - 46665 (2014/12/10)
A simple and efficient method for the synthesis of pyranoid glycals utilizing the reductive elimination of glycopyranosyl bromides by zinc nanoparticles in an acetate buffer is described. A variety of pyranoid glycals derivatives were obtained, especially for the synthesis of 6-deoxy-4,6-O-benzylidene and disaccharide glycals with good yields.
Epimerization of glycal derivatives by a cyclopentadienylruthenium catalyst: Application to metalloenzymatic DYKAT
Lihammar, Richard,R?nnols, Jerk,Widmalm, G?ran,B?ckvall, Jan-E.
, p. 14756 - 14762 (2015/04/16)
Epimerization of a non-anomeric stereogenic center in carbohydrates is an important transformation in the synthesis of natural products. In this study an epimerization procedure of the allylic alcohols of glycals by cyclopentadienylruthenium catalyst 1 is presented. The epimerization of 4,6-O-benzylidene-d-glucal 4 in toluene is rapid, and an equlibrium with its d-allal epimer 5 is established within 5 min at room temperature. Exchange rates for allal and glucal formation were determined by 1D 1H EXSY NMR experiments to be 0.055 s-1 and 0.075 s -1, respectively. For 4-O-benzyl-l-rhamnal 8 the epimerization was less rapid and four days of epimerization was required to achieve equilibration of the epimers at room temperature. The epimerization methodology was subsequently combined with acylating enzymes in a dynamic kinetic asymmetric transformation (DYKAT), giving stereoselective acylation to the desired stereoisomers 12, 13 , and 15. The net effect of this process is an inversion of a stereogenic center on the glycal, and yields ranging from 71% to 83% of the epimer were obtained.
Oxidative addition of secondary C-X bonds to palladium(0): A beneficial anomeric acceleration
Munro-Leighton, Colleen,Adduci, Laura L.,Becker, Jennifer J.,Gagne, Michel R.
scheme or table, p. 2646 - 2649 (2011/06/27)
The oxidative addition of secondary electrophiles to Pd(0) is significantly accelerated by anomeric effects. In contrast to cyclohexyl bromide, acetobromo-α-d-glucose undergoes invertive oxidative addition to tris(triethylphosphine)palladium(0) to generate a stable, isolable organometallic complex, Pd(PEt3)2(Br)(AcO-β-glucose), which has been fully characterized but is prone to β-acetoxy elimination.
A facile synthesis of 4,6-O-benzylidene-d-glycals via 1,5-anhydro-4,6-O-benzylidene-d-hex-1-en-3-ulose
Sakakibara, Tohru,Ito, Tsubasa,Kotaka, Chika,Kajihara, Yasuhiro,Watanabe, Yuhya,Fujioka, Aki
experimental part, p. 2740 - 2743 (2009/04/11)
Benzylidenation of readily available 1,5-anhydro-d-hex-1-en-3-ulose, followed by sodium borohydride reduction, afforded the title compounds in high yields. Separation of 4,6-O-benzylidene-d-allal and -d-glucal was accomplished by selective acetylation wit
Stereoselective synthesis of C-glycosides from carboxylic acids: The tandem Tebbe-Claisen approach
Godage, H. Yasmin,Chambers, David J.,Evans, Graham R.,Fairbanks, Antony J.
, p. 3772 - 3786 (2007/10/03)
A variety of β- or α-C-glycosides may be readily accessed in an entirely stereoselective fashion from esters derived from the reaction of carboxylic acids and 3-hydroxy glycals, by way of a tandem reaction sequence of Tebbe methylenation and Claisen rearrangement. Though of wide scope, for example allowing the synthesis of 1-6 linked C-disaccharides, the methodology does not currently allow the synthesis of C-glycosyl α-amino acids.
Stereoselective synthesis of C-glycosides via Tebbe methylenation and Claisen rearrangement
Godage,Fairbanks
, p. 7589 - 7593 (2007/10/03)
A variety of β-C-glycosides may be readily accessed in a stereoselective fashion from 3-OH glycal esters, via the use of Tebbe methylenation and subsequent thermal Claisen rearrangement. The use of carbohydrate ester substrates allows the formation of β(1
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
Reductive elimination of glycosyl phenyl sulfones by SmI2-HMPA: A convenient synthesis of substituted pyranoid glycals
De Pouilly, Pierre,Chenede, Alain,Mallet, Jean-Maurice,Sinay, Pierre
, p. 8065 - 8068 (2007/10/02)
A series of substituted glycosyl phenyl sulfones was converted into glycals after reductive samariation with SmI2 in the presence of hexamethylphosphoric triamide, followed by elimination of the substituent at C-2. Practically quantitative yields were obtained when the leaving group was an acetate, as illustrated here with seven substrates.
An Approach to the Total Synthesis of the Prelog-Djerassi Lactone
Jones, Keith,Wood, William W.
, p. 537 - 546 (2007/10/02)
An approach to the synthesis of the Prelog-Djerassi lactone using D-glucose as a starting material is described.The use of Swern oxidation provides an efficient means of preparing carbohydrate ketones.An unusual departure from the normal reaction pathway
