93836-22-7Relevant academic research and scientific papers
Mild cu(Otf)2-mediated C-glycosylation with chelation-assisted picolinate as a leaving group
Tang, Weiping,Ye, Wenjing,Stevens, Christopher M.,Wen, Peng,Simmons, Christopher J.
, p. 16218 - 16225 (2021/01/19)
C-Glycosylation reactions of glycosyl picolinates with allyltrimethylsilane or silyl enol ethers were developed. Picolinate as a chelation-assisted leaving group could be activated by Cu(OTf)2 and avoided the use of harsh Lewis acids. The glycosylations were operated under mild neutral conditions and gave the corresponding C-glycosides in up to 95% yield with moderate to excellent stereoselectivities.
"Design" of boron-based compounds as pro-nucleophiles and co-catalysts for indium(I)-catalyzed allyl transfer to various Csp 3-type electrophiles
Dao, Hai Thanh,Schneider, Uwe,Kobayashi, Shu
experimental part, p. 2522 - 2529 (2012/07/13)
We have recently uncovered a general indium(I)-catalyzed method for allylations and propargylation of acetals and ketals with a water- and air-stable allyl boronate. By using a more reactive allyl borane, we have successfully extended this methodology to the more challenging C-C coupling with ethers. Herein, we report an improved methodology for the indium(I)-catalyzed allylation of acetals and ethers, through combination of the allyl boronate with a commercially available "hard" Lewis acid, B-methoxy-9-BBN (BBN=borabicyclo[3.3.1]nonane), as an effective co-catalyst. Significantly, our work highlights for the first time the correlation between the Lewis acidity of "electrophilic" boron-based compounds and their " nucleophilic" reactivity in Csp3-Csp3 couplings, catalyzed by a "soft" low-oxidation main group metal. In addition, we also report several applications of these methodologies to the selective synthesis of various carbohydrate derivatives. Copyright
Stereocontrolled photocyclization of 1,2-diketones: Application of a 1,3-acetyl group transfer methodology to carbohydrates
Herrera, Antonio J.,Rondon, Maria,Suarez, Ernesto
, p. 3384 - 3391 (2008/09/21)
(Chemical Equation Presented) Photolysis of 1-glycosyl-2,3-butanodione derivatives using visible light is a mild and selective procedure for the synthesis of chiral 1-hydroxy-1-methyl-5-oxaspiro[3.5]nonan-2-one carbohydrate derivatives. The results strongly suggest that stereocontrol of the cyclization is dependent on conformational and stereoelectronic factors. Further oxidative opening of the 1-hydroxy-1-methyl-2-cyclobutanone moiety affords new C-ketoside derivatives either in C- and O-glycoside series. This tandem two-step process could be considered to be a stereocontrol led 1,3-transference of an acetyl group, and it can be applied either to pyranose and furanose models.
Synthesis of C-5-thioglycopyranosides and their sulfonium derivatives from 1-C-(2′-oxoalkyl)-5-S-acetylglycofuranosides
Yi, Tian,Wu, Shih-Hsiung,Zou, Wei
, p. 235 - 244 (2007/10/03)
1-C-(2′-oxoalkyl)-5-S-acetylglycofuranosides of l-arabinose, d-ribose, and d-xylose were converted to 1-C-(2′-oxoalkyl)-5- thioglycopyranosides by base treatment. The transformation was achieved through β-elimination to an acyclic α,β-conjugated aldehyde (ketone or ester), followed by an intramolecular hetero-Michael addition by the 5-thiol group. The cycloaddition was highly stereoselective in favor of an equatorial 1-C-substitution. The resultant C-5-thioglycopyranosides were further converted to the sulfonium salts by treatment with cyclic sulfate and methyl iodide. Two sulfonium isomers were obtained due to the presence of both S-axial and S-equatorial substitutions. We observed that the chemical shifts of both C-1 and C-5 in the S-axial substituted sulfonium sugars are always shifted up-field (5-10 ppm) in comparison to those in the S-equatorial substitutions (δC 49-53 ppm vs 42-45 ppm at C-1 and 37-42 ppm vs 32-35 ppm at C-5), which provides an easy way for determination of the stereochemistry. Crown Copyright
Scandium(III) perchlorate (Sc(ClO4)3). A novel catalyst in the α-C- and N-glycosylation reactions
Hachiya,Kobayashi
, p. 3319 - 3320 (2007/10/02)
In the presence of a catalytic amount of scandium(III) perchlorate (Sc(ClO4)3), 1-O-acetyl-2,3,5-tri-O-benzyl-β-D-ribofuranose reacted with trimethylsilylated nucleophiles to afford the corresponding α-D-ribofuranosides in high yield
Stereoselective 1,2-cis Glycosylation Reaction of 1-O-Acetylribose with Silylated Nucleophiles by the Promotion of a New Catalyst System
Mukaiyama, Teruaki,Shimpuku, Tetsuro,Takashima, Tohru,Kobayashi, Shu
, p. 145 - 148 (2007/10/02)
1,2-cis-Ribofuranosides are stereoselectively prepared in high yields by the reaction of 1-O-acetyl-β-D-ribose with silylated nucleophiles by the promotion of a new catalyst system, the combined use of a catalytic amount of tin(IV) chloride and tin(II) tr
HIGHLY STEREOSELECTIVE C-α-D-RIBOFURANOSYLATION. REACTIONS OF D-RIBOFURANOSYL FLUORIDE DERIVATIVES WITH ENOL TRIMETHYLSILYL ETHERS AND ALLYLTRIMETHYLSILANE
Araki, Younosuke,Kobayashi, Naoki,Ishido, Yoshiharu,Nagasawa, Jun'ichi
, p. 125 - 140 (2007/10/02)
2,3,5-Tri-O-methyl-D-ribofuranosyl fluoride (6), 2,3-di-O-benzyl-5-O-methyl-D-ribofuranosyl fluoride (7), and 5-O-benzyl-2,3-di-O-methyl-D-ribo-furanosyl fluoride (8) were obtained in 57 (6α, 15; and 6β, 42), 87 (7α, 22; and 7β, 65) and 85.5 (8α, 35.5; an
A CONVENIENT SYNTHESIS OF C-α-D-RIBOFURANOSYL COMPOUNDS FROM 1-O-ACETYL-2,3,5-TRI-O-BENZYL-β-D-RIBOSE BY THE PROMOTION OF TRIPHENYLMETHYL PERCHLORATE
Mukaiyama, Teruaki,Kobayashi, Shu
, p. 81 - 88 (2007/10/02)
In the presence of a catalytic amount of triphenylmethyl perchlorate (trityl perchlorate), 1-O-acetyl-2,3,5-tri-O-benzyl-β-D-ribose stereoselectively reacted with trimethylsilyl nucleophiles, such as trimethylsilyl enol ether, allylsilane, and trimethylsi
A FACILE SYNTHESIS OF Α-C-RIBOFURANOSIDES FROM 1-O-ACETYL RIBOSE IN THE PRESENCE OF TRITYL PERCHLORATE
Mukaiyama, Teruaki,Kobayashi, Shu,Shoda, Shin-ichiro
, p. 1529 - 1530 (2007/10/02)
In the presence of a catalytic amount of trityl perchlorate, 1-o-acetyl ribose stereoselectively reacts with silylated nucleophiles, such as silyl enol ether, allylsilane, and trimethylsilyl cyanide, to give the corresponding α-C-ribofuranosides in excell
