β-Anomer selectivity in 2′-deoxynucleoside synthesis: A novel approach using an acyl carbamate directing group

Young, Robert J.; Shaw‐Ponter, S.; Hardy, G.; Mills, G.

doi:10.1016/s0040-4039(00)78472-3

Cited by 26 publications

(6 citation statements)

References 12 publications

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“…Stereoselective N-glycosylations with a 2-deoxyribofuranosyl donor, possessing an N-benzoylcarbamoyl group at the O-3 position, as a directing group, were reported by Young and coworkers in 1994 (26). Glycosylation of persilylated base 90 with 2-deoxyribofuranosyl donor 89 afforded deoxyribonucleoside 91 (α/β = 1:14) with a large excess of the β-anomer (Scheme 18).…”

Section: The Remote Participation In Glycofuranosylationmentioning

confidence: 97%

Remote Participation of Protecting Groups at Remote Positions of Donors in Glycosylations

Kim

Suk

2011

TIGG

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Effects of potentially participating groups at remote positions of glycopyranosyl and glycofuranosyl donors on the glycosylation stereochemistry are reviewed. Substantial evidences in favor of the remote participation by protecting groups are presented and also included are a few reports opposed to the remote participation. A. IntroductionT h e p r o t e c t i n g g r o u p s i n t h e o l i g o s a c c h a r i d e synthesis are used to selectively block interfering functions as well as influence the reactivity and stereoselectivity in the glycosylation steps. The anchimeric assistance of a neighboring participating group such as an acyl group at the O-2 position of the glycosyl donor has been one of the most useful strategies for the stereoselective formation of 1,2-trans glycosides (1−5). The carbonyl functionality at the O-2 position of the glycosyl donor can attack an incipient oxonium ion to give a dioxonium ion. Nucleophilic attack by an acceptor to the opposite face of the dioxonium ion provides the 1,2-trans glycoside. When potentially participating groups are located at remote positions other than the O-2 position of glycosyl donors, the existence of the remote participation by the remote protecting groups in the glycosylation step has been controversial. Although numerous examples for glycosylations with glycosyl donors possessing potentially participating groups at remote positions can be found in the literature, most of them do not provide any information on the remote participation by protecting groups in glycosylations. There have been reports both in favor of and opposed to the remote participation by protecting groups in glycosylations. Herein we review the effects of potentially participating protecting groups at remote positions of glycopyranosyl and glycofuranosyl donors on the glycosylation stereochemistry. Further, we present substantial evidence in favor of the remote participation by protecting groups and also include a few reports that are opposed to remote participation.

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Section: The Remote Participation In Glycofuranosylationmentioning

confidence: 97%

Remote Participation of Protecting Groups at Remote Positions of Donors in Glycosylations

Kim

Suk

2011

TIGG

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“…Then 5 0 -O-Benzyl-1 0 -O-acetyl-ribofuranose 4 was used for the coupling reaction because AcO is a better C-1 0 -leaving group at À78°C, and the b-selectivity was improved remarkably (b/a = 98/2, Table 2, entry 1). It is worth noting that the reaction could be completed within 2 h. 9 To further investigate the scope of this method, we examined the reactions with different heterocyclic bases including N 4 -benzoylcytosine, N 6 -benzoyladenine, and N 2 -benzoyl-guanine. All the coupling reactions provided high b-selectivities and good yields (Table 2).…”

Section: Tablementioning

confidence: 99%

Highly stereoselective synthesis of 2′-deoxy-β-ribonucleosides via a 3′-(N-acetyl)-glycyl-directing group

Liu

Yin

et al. 2010

Tetrahedron Letters

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“…42 Young has also activated a thioglycoside, for 2'-deoxynucleoside synthesis. 72 Noting the desirability of a site-selective low-temperature N-glycosylation method for the synthesis of complex nucleoside antibiotics, we showed73 95% that the van Boom conditions74 (AModosuccinimide, triflic acid) applied to nucleoside synthesis allowed the efficient conversion of (alkyl or aryl) 1-thiopyranosides and 1-thiofuranosides to various pyrimidine and purine nucleosides (Scheme 3, entry 2). This reaction was later used as a key step in our capuramycin synthesis,33 and Gamer has used it for selective N-7 purine glycosylation.52 Beau showed in 1992 that phenyl l-deoxy-l-thio-2,3,5-tri-0-benzoyl-D-ribofuranoside S-oxide reacted with silylated nucleobases in the presence of trimethylsilyl trifluoromethanesulfonate (an adaptation of the Kahne glycosylation75) to give the nucleosides in good yields, and used the reaction to prepare (l'-13C) labeled 2'deoxynucleoside building blocks (Scheme 3, entry 3).…”

Section: Analysis Of Tacticsmentioning

confidence: 99%

Synthesis of Complex Nucleoside Antibiotics

Knapp¹

1995

Chem. Rev.

321

116

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C. Notable Targets Approached but Not Yet 1860 Synthesized II. Analysis of Synthetic Strategy 1860 A. Convergence 1860 B. Early vs Late W-Glycosylation 1862 III. Analysis of Tactics 1862 A. Final Deprotection 1862 B. W-Glycosylation (Nucleoside Formation) 1863 C. OGIycosylation (Disaccharide Formation) 1868 1. O-Glycosylation of Sugars 1868 2. OGIycosylation of Nucleosides 1869 D. Peptide Bond Formation 1871 E. Synthesis of the Components 1872 1. C-C Bond Formation in the Completed 1872 Syntheses 2. Components Synthesized in Model 1875 Studies and Approaches, 1988 to Mid-1995 I. Assessment of Current Status A. Introduction and CoverageComplex nucleoside antibiotics comprise an extensive array of natural products notable for combining the structural features of nucleosides, higher monosaccharides, disaccharides, peptides, and lipids. In some representatives there is unusual functionality that even goes beyond these contexts. The complex nucleoside antibiotics exhibit a variety of biological activities, including antifungal, anthelmintic, herbicidal, insecticidal, antiviral, and antitumor. This review will discuss, with emphasis on the impressive accomplishments of the last several years (1988 to mid-1995), the strategies and tactics that have led to the synthesis of a growing collection of complex nucleoside antibiotics. The review by Gar-ner1 has detailed synthetic approaches to these compounds through 1987, and the 1988 and 1991 reviews by Isono2 3 describe the structures, biological activities, and biosynthesis of nucleoside antibiotics including a number of simpler nucleoside and nucleotide analogues that will not be covered here. In 1991, Lerner4 reviewed the synthesis and properties of various disaccharide nucleosides, including some with relatively simple pyranoside and furanoside components that likewise will not be covered in this review. Thus the emphasis here is on the most complex of the complex nucleoside antibiotics (pre-

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β-Anomer selectivity in 2′-deoxynucleoside synthesis: A novel approach using an acyl carbamate directing group

Cited by 26 publications

References 12 publications

Remote Participation of Protecting Groups at Remote Positions of Donors in Glycosylations

Remote Participation of Protecting Groups at Remote Positions of Donors in Glycosylations

Highly stereoselective synthesis of 2′-deoxy-β-ribonucleosides via a 3′-(N-acetyl)-glycyl-directing group

Synthesis of Complex Nucleoside Antibiotics

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