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Journal ArticleDOI

Recent Developments in the Ferrier Rearrangement

01 Nov 2013-European Journal of Organic Chemistry (John Wiley & Sons, Ltd)-Vol. 2013, Iss: 32, pp 7221-7262
TL;DR: A review of recent developments in the use of promoters for the Ferrier rearrangement of O-, N-, C- and S-nucleophiles with glycals can be found in this paper.
About: This article is published in European Journal of Organic Chemistry.The article was published on 2013-11-01. It has received 121 citations till now. The article focuses on the topics: Ferrier rearrangement & Ferrier carbocyclization.
Citations
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Journal ArticleDOI
TL;DR: This Review covers classical approaches to deoxyglycoside synthesis, as well as more recently developed chemistry that aims to control the selectivity of the reaction through rational design of the promoter.
Abstract: Deoxy-sugars often play a critical role in modulating the potency of many bioactive natural products. Accordingly, there has been sustained interest in methods for their synthesis over the past several decades. The focus of much of this work has been on developing new glycosylation reactions that permit the mild and selective construction of deoxyglycosides. This Review covers classical approaches to deoxyglycoside synthesis, as well as more recently developed chemistry that aims to control the selectivity of the reaction through rational design of the promoter. Where relevant, the application of this chemistry to natural product synthesis will also be described.

194 citations

Journal ArticleDOI
TL;DR: This review highlights the C-glycosylation methods that have been practised in the total synthesis of natural products and pharmaceuticals in the past decade.
Abstract: Chemical C-glycosylation has been well developed to improve stereoselectivity in recent years. Due to its high efficiency to build C-glycosides or O-cyclic compounds, C-glycosylation has found widespread use in the synthesis of biologically active molecules. This review highlights the C-glycosylation methods that have been practised in the total synthesis of natural products and pharmaceuticals in the past decade.

75 citations

Journal ArticleDOI
TL;DR: In the last few years, considerable progress has been made in the synthesis of C-glycosides as mentioned in this paper, and due to its versatility, C glycosides play a pivotal role in developing novel materials, surfactants and bioactive molecules.

69 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluate the fundamental connections between the anomeric effect and a broad variety of O-functional groups and highlight the vast implications of AE for the structure and reactivity of organic O-functionalities.
Abstract: Although carbon is the central element of organic chemistry, oxygen is the central element of stereoelectronic control in organic chemistry. Generally, a molecule with a C–O bond has both a strong donor (a lone pair) and a strong acceptor (e.g., a σ*C–O orbital), a combination that provides opportunities to influence chemical transformations at both ends of the electron demand spectrum. Oxygen is a stereoelectronic chameleon that adapts to the varying situations in radical, cationic, anionic, and metal-mediated transformations. Arguably, the most historically important stereoelectronic effect is the anomeric effect (AE), i.e., the axial preference of acceptor groups at the anomeric position of sugars. Although AE is generally attributed to hyperconjugative interactions of σ-acceptors with a lone pair at oxygen (negative hyperconjugation), recent literature reports suggested alternative explanations. In this context, it is timely to evaluate the fundamental connections between the AE and a broad variety of O-functional groups. Such connections illustrate the general role of hyperconjugation with oxygen lone pairs in reactivity. Lessons from the AE can be used as the conceptual framework for organizing disjointed observations into a logical body of knowledge. In contrast, neglect of hyperconjugation can be deeply misleading as it removes the stereoelectronic cornerstone on which, as we show in this review, the chemistry of organic oxygen functionalities is largely based. As negative hyperconjugation releases the “underutilized” stereoelectronic power of unshared electrons (the lone pairs) for the stabilization of a developing positive charge, the role of orbital interactions increases when the electronic demand is high and molecules distort from their equilibrium geometries. From this perspective, hyperconjugative anomeric interactions play a unique role in guiding reaction design. In this manuscript, we discuss the reactivity of organic O-functionalities, outline variations in the possible hyperconjugative patterns, and showcase the vast implications of AE for the structure and reactivity. On our journey through a variety of O-containing organic functional groups, from textbook to exotic, we will illustrate how this knowledge can predict chemical reactivity and unlock new useful synthetic transformations.

60 citations

Journal ArticleDOI
TL;DR: This review summarizes the literature on the different transformations of the endo glycals into biologically relevant compounds as well as on the use of glycals as chiral building blocks for the synthesis of various natural products such as aspicilin, reblastatin, diospongins, decytospolides, osmundalactones, paclitaxel, isatisine, d-fagomine, and spliceostatin, reported post 2014.
Abstract: Glycals, 1,2-unsaturated sugar derivatives, are versatile starting materials for the synthesis of natural products and the generation of novel structural features in Diversity Oriented Synthesis (DOS). The versatility of glycals in synthesis emanates, among others, from the presence of the ring oxygen and the enol-ether type unsaturation, the different types of stable conformations they can adopt depending on the nature of the protecting groups present and the ease with which the protecting groups of the three hydroxy groups could be tailored to suite for a desired manipulation. This review summarizes the literature on the different transformations of the endo glycals into biologically relevant compounds such as chromans, thiochromans, chromenes, thiochromenes, peptidomimetics, bridged benzopyrans etc., as well as on the use of glycals as chiral building blocks for the synthesis of various natural products such as aspicilin, reblastatin, diospongins, decytospolides, osmundalactones, paclitaxel, isatisine, D-fagomine, and spliceostatin, reported post 2014.

37 citations

References
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Journal ArticleDOI
TL;DR: Al(OTf)3 was found to be an extremely effective catalyst (at ppm levels) for ring opening reactions of epoxides using a range of alcohols.
Abstract: Al(OTf)3 was found to be an extremely effective catalyst (at ppm levels) for ring opening reactions of epoxides using a range of alcohols.

93 citations

Book ChapterDOI
TL;DR: This chapter surveys the chemistry of most of the important types of monosaccharide derivatives that contain single alkene groups—notably, the glycols that are extremely valuable starting materials for a vast range of synthetic transformations.
Abstract: Publisher Summary This chapter discusses the synthesis and reactions of unsaturated sugars. Sugar derivatives that contain double bonds have been developed and used so extensively that they almost certainly constitute the most versatile category of carbohydrate compounds available for use in synthesis of unsaturated sugars. They may be applied both in the synthesis of complex members of the family and of a myriad enantiomerically pure noncarbohydrate compounds—notably, many of interest in medicinal chemistry. In addition, some unsaturated sugar derivatives have themselves been found to possess important therapeutic properties. The unnatural L-nucleoside inhibits reverse transcriptase and shows potent and selective anti-AIDS activity. This chapter surveys the chemistry of most of the important types of monosaccharide derivatives that contain single alkene groups—notably, the glycols that are extremely valuable starting materials for a vast range of synthetic transformations. It also discusses the preparation of the reactions of glycols, elaborates the synthesis of pyranoid and furanoid 2- and 3-Enes, and explains the chemistry of endo-Enes and exo-Enes.

90 citations

Journal ArticleDOI
TL;DR: Lys182 may be an alternative candidate for the active-site acid according to a Scheme 32 Scheme 33 4648 Chemical Reviews, 2000, Vol.
Abstract: ion at 2-OH of the substrate, a process that also leads to further movement of this metal.310,315 It is proposed that the protein ligands Asp254 and Asp256 dissociate from Mg-2 at this stage and are replaced by a water molecule, O-1, and O-2 of the substrate (105).284,305 Thus, the developing negative charge at O-2 is stabilized by both Mg-1 and Mg-2, which in turn pulls the metal centers closer to establish a proper geometry to facilitate the isomerization step (105).305,308 As depicted in Scheme 33, after tautomerization the partial negative charge generated at O-1 may be stabilized by Lys182 (106).298,301,305,316 This lysine residue together with the metal ions confines the extended reaction intermediate in a syn-conformation and thus determines the stereochemical course of the hydride shift process.284,285 The Mg-2-bound water molecule has been proposed to be the proton donor to O-1 (106).277,285,310,317 Lys182 may be an alternative candidate for the active-site acid according to a Scheme 32 Scheme 33 4648 Chemical Reviews, 2000, Vol. 100, No. 12 He et al.

84 citations