Glycosidation Promoted by a Reusable Solid Superacid in Supercritical Carbon Dioxide

Li, Xuebing; Ogawa, Masato; Monden, Toshiki; Maeda, Takahiro; Yamashita, Eri; Naka, Mariko; Matsuda, Masao; Hinou, Hiroshi; Nishimura, Shin‐Ichiro

doi:10.1002/anie.200602161

Cited by 14 publications

(4 citation statements)

References 39 publications

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“…Sulfated zirconia (SO 4 /ZrO 2 or “SZ”), a commercially available, solid superacid was investigated as a novel catalyst for TCA activation by the Nishimura group in 2006 using supercritical CO 2 (“scCO 2 ”) as the solvent . This was an environmental friendly approach since it involved no organic solvents and a reusable catalyst.…”

Section: Glycosyl Imidate Donorssupporting

confidence: 85%

Catalytic Glycosylations in Oligosaccharide Synthesis

2018

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Catalytic glycosylation has been a central reaction in carbohydrate chemistry since its introduction by Fischer 125 years ago, but it is only in the past three to four decades that catalytic methods for synthesizing oligosaccharides have appeared. Despite the development of numerous elegant and ingenious catalytic glycosylation methods, only a few are in general use. This review covers all methods of catalytic glycosylation with the focus on the development and application in oligosaccharide synthesis and provide an overview of the scope and limitations of these. The review also includes relevant mechanistic studies of catalytic glycosylations. The future of catalytic glycosylation chemistry is discussed, including specific, upcoming methods and possible directions for the field of research in general.

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Section: Glycosyl Imidate Donorssupporting

confidence: 85%

Catalytic Glycosylations in Oligosaccharide Synthesis

2018

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“…According to these features, scCO 2 is far from being an ideal solvent for S N 1 reactions in the absence of strong acids. Acid-catalyzed reactions, such as Friedel-Crafts alkylation with alcohols, [7] alkane isomerization, [8] glycosidation, [9] and etherification, [10] are known to proceed efficiently in scCO 2 , although the involvement of carbocation intermediates has not been specifically ascertained. As these reports suggest that scCO 2 is able to sustain ionic processes, they prompted us to test the ability of scCO 2 to promote S N 1 reactions in the absence of acid catalysts.…”

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confidence: 99%

Supercritical Carbon Dioxide: A Promoter of Carbon–Halogen Bond Heterolysis

et al. 2013

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Amazing reaction medium: Supercritical carbon dioxide, with zero dipole moment, lower dielectric constant than pentane, and non‐hydrogen‐bonding behavior, ionizes carbon–halogen bonds, dissociates the resulting ion pairs, and escapes from capture by the carbocation intermediates at temperatures above 40 °C. These properties allow the observation of carbocation chemistry in the absence of acids.

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“…As a reaction medium, scCO 2 has been used in diverse synthetic processes with varying results. 10 In the specific case of carbohydrate chemistry, glycosidation reaction 11 has been described under metal-free conditions 12 and in the presence of sulfated zirconia 13 with scCO 2 as the solvent. To the best of our knowledge, the direct glycosylation of ceramides to obtain glycosphingolipids (GSLs) in scCO 2 has not been previously explored.…”

Section: Oxide Montmorillonitementioning

confidence: 99%