Toward a Carbohydrate-Based Chemistry:  Progress in the Development of General-Purpose Chiral Synthons from Carbohydrates

Hollingsworth, Rawle I.; Wang, Guijun

doi:10.1021/cr990374e

Cited by 114 publications

(48 citation statements)

References 120 publications

(149 reference statements)

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“…In recent years, research in this field has focused on converting biomass into chemicals that are envisioned as high-volume commodities 3 , as breakthroughs in these large-scale processes would be highly impactful 4,5 . For example, bioethanol 6 and the aromatic hydroxymethyl furfural (HMF) 7 are important examples in which overfunctionalized carbohydrate-based biomass is fermented or selectively deoxygenated through elimination to realize useful platform feedstocks [8][9][10][11] .…”

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confidence: 99%

Chemoselective conversion of biologically sourced polyols into chiral synthons

et al. 2015

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Crude oil currently provides much of the world's energy, but it is also the source of many feedstock chemicals. Methodology for the conversion of biomass into useful chemicals has often focused on either complete deoxygenation or the production of high-volume platform chemicals. Here, we describe the chemoselective partial reduction of silyl-protected C6O6-derived polyols to produce a diverse set of oxygen-functionalized chiral synthons. The combination of B(C6F5)3 and a tertiary silane efficiently generates a reactive equivalent of an electrophilic silylium ion (R3Si(+)) and a hydride (H(-)) reducing agent. The mechanism of oxygen loss does not involve a dehydrative elimination and thus avoids ablation of stereochemistry. Neighbouring group participation and the formation of cyclic intermediates is key to achieving selectivity in these reactions and, where both primary and secondary C-O bonds are present, the mechanism allows further control. The method provides--in one or two synthetic steps--highly improved syntheses of many C6On synthons as well as several previously undescribed products.

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confidence: 99%

Chemoselective conversion of biologically sourced polyols into chiral synthons

et al. 2015

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“…The molecular diversity of carbohydrates makes them valuable molecular scaffolds; the high density of functional groups per mass unit has always challenged synthetic chemists toward a multitude of approaches to this rich class of compounds. Carbohydrates provide rigid molecular systems which can be used as molecular templates to display functional groups in well defined spatial orientations [5]. In addition, carbohydrates impart different and variable physicochemical properties in macromolecules where they are included; good examples are chitosans [6], or hyaluronic acids [7].…”

Section: Introductionmentioning

confidence: 99%

Glycans in Magnetic Resonance Imaging: Determinants of Relaxivity to Smart Agents, and Potential Applications in Biomedicine

Cipolla¹,

Gregori²,

2011

CMC

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Carbohydrate chemistry and glycobiology have become a "hot" subject. These extensive, complex structures serve essential roles in cell surface phenomena, but we are only beginning to understand what some of these functions are; any advances in the development of synthetic and/or analytical tools for glycobiology are extremely useful for our understanding of the roles of carbohydrates in biology, and as biomarkers of physiological/pathological states. This review provides an outlook of the potential of carbohydrate chemistry/biology in magnetic resonance imaging (MRI), a major important and prominent technique in diagnostic clinical medicine and biomedical research. During the last 30 years, MRI has developed from an intriguing research project to an essential diagnostic method in the clinic. Although MRI contrast in endogenous tissues provides excellent sensitivity for detecting subtle changes in anatomy and function, MRI still has poor specificity for attributing image contrast to specific biological processes. To overcome this limitation, MRI methods are being developed that induce changes in MR image contrast in response to molecular compositions and functions that serve as early biomarkers of pathologies. Carbohydrates with their intriguing chemistry, not only can provide structures for novel MRI probes for imaging specific biological processes, but can themselves provide novel targets/biomarkers. For example, the glycan structure can simply provide a molecular scaffold for modulating the physicochemical properties of the imaging contrast agent, or can be used for the design of novel MR agents with the ability to disclose relevant physiological or pathological cellular events.

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“…The rapidly growing interest in the biological roles of glycoconjugates (glycoproteins, glycolipids and proteoglycans) [2] requires homogeneous materials to study. On other hand, carbohydrates, which contain several functional groups and stereogenic centres in one molecular unit, are important as tools in stereochemical differentiation, as starting materials in the synthesis of interesting enantiopure compounds, [3] as chiral templates in asymmetric transformations [4] and as chiral auxiliaries in stereoselective synthesis. [5] In this sense we have used amino sugars as chiral templates in the stereoselective synthesis of diamino sugars, [6] chiral oxazolidines, [7] chiral oxiranes, [8] chiral cyclopropanes [9] and compounds with potential anticancer activity.…”

Section: Introductionmentioning

confidence: 99%