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.
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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
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
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
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
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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TL;DR: In this paper, a chiral pyrano[2,3-b] benzopyrans were synthesized by reaction of 2-C-acetoxymethylglycals 1 and 2 with phenols under Lewis acid catalysis.
37 citations
TL;DR: In this paper, the Ferrier glucosylation of alcohols with 3,4,6-tri- O-acetyl-d-glucal has been investigated with several metal nitrates and the optimal catalyst is bismuth nitrate pentahydrate (BNP).
Abstract: The Ferrier glucosylation of alcohols with 3,4,6-tri- O-acetyl-d-glucal has been investigated with several metal nitrates and the optimal catalyst is bismuth nitrate pentahydrate (BNP). Good yields of pseudoglycals were also obtained with ferric nitrate nonahydrate (FNN), heightening the catalyst dosage (50 mol%) being required however. The BNP-mediated reactions showed remarkable solvent dependency and in the optimal protocol, the amount of BNP as low as 10 mol% was effective, furnishing excellent yields of O-glucosides with good anomeric selectivity in acetonitrile. A comparison of BNP and FNN in terms of yields and selectivity of the product has been made. In comparison to the reactions in acetonitrile, the catalytic ability of BNP was found to enhance drastically in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF 6]. © 2005 Elsevier B.V. All rights reserved.
37 citations
TL;DR: Synthesis of 2-deoxy-1-thioglycosides from glycals, mediated by catalytic amounts of ceric ammonium nitrate is reported, and formation of the 2,3-unsaturated enose, corresponding to the Ferrier product, is observed.
36 citations
TL;DR: The use of C- Glycoside Michael acceptors, as opposed to their O-glycoside counterparts, represents a potentially useful simplification of phthalide annulation methodology in synthesizing numerous other such optically pure isochromanquinoids, since it obviates the inconvenience of additional steps late in the synthetic scheme associated with reductive manipulation of a remaining acetal moiety into the desired pyran ring substituent.
Abstract: Optically pure enone 9c, available in three steps from known 6-deoxy D-galactal derivative 7b, reacts with cyanophthalide 6 to directly afford the natural product (-)-hongconin (1), a compound from traditional Chinese medicine recently shown to exhibit antianginal activity. The enantiomer of 1 and its (+)-cis-diastereomer were also synthesized in a parallel fashion from the L-sugar counterpart. The use of C-glycoside Michael acceptors, as opposed to their O-glycoside counterparts, represents a potentially useful simplification of phthalide annulation methodology in synthesizing numerous other such optically pure isochromanquinoids, since it obviates the inconvenience of additional steps late in the synthetic scheme associated with reductive manipulation of a remaining acetal moiety into the desired pyran ring substituent.
36 citations
TL;DR: NbCl 5 catalyzes the Ferrier reaction of per-O -acetylated glycals with primary, secondary, allylic, benzylic and monosaccharide alcohols to give 2,3-unsaturated α-glycosides in short reaction times under microwave irradiation conditions.
35 citations