An Attempt at the Direct Construction of 2-Deoxy-β-glycosidic Linkages Capitalizing on 2-Deoxyglycopyranosyl Diethyl Phosphites as Glycosyl Donors

Hashimoto, Shunichi; Sano, Ai; Sakamoto, Hiroki; Nakajima, Makoto; Yanagiya, Yuki; Ikegami, Shiro

doi:10.1055/s-1995-5254

Cited by 70 publications

(31 citation statements)

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“…The less polar compound was identical in all respects with a sample kindly provided by Prof. J. Rohr. [32] NMR data of 3: 588 Krohn, Agocs, and Bäuerlein…”

Section: Diacetate 14mentioning

confidence: 99%

“…XVII 583 observed depending on the duration of the Zemplén saponification procedure. This compound would be ideally suited for further attachment of deoxysugars, for instance employing the selective a-glycoside synthesis using 2-deoxyglycosyl phosphates as proposed by Hashimoto [32] and recently employed by Sulikowski et al [33] In summary, the regioselective NBS bromination of the tetraacetate 7 allowed the large-scale preparation of the quinoid D-olivose-C-glycoside 8. The aglycone was constructed by Diels -Alder reaction and the stereoselective a-L-rhodinose-O-glycoside by using monoalcohol 15 and L-benzoylrhodinal (16) and scandium triflate as the promotor.…”

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confidence: 99%

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Total Synthesis of Angucyclines. XVII. First Synthesis of Antibiotic 100‐1, a Deoxydisaccharide Angucycline Antibiotic of the Urdamycinone B‐Type

Krohn

Agócs

Bäuerlein

2003

Journal of Carbohydrate Chemistry

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Two routes to the deoxydisaccharide angucycline antibiotic 100-1 (3) are described. Key steps comprise the regioselective oxidation/bromination of the 1,5-diacetoxyolivose C-saccharide 7 to the bromoquinone 8. Diels -Alder reaction of the bromoquinone with the diene 9 followed by HBr elimination afforded the urdamycinone B precursor 11 as a diastereomeric mixture. Selective protection as the TBDMS ether 13, acetylation and deprotection of the silyl ether afforded the alcohol 15 which was selectively glycosylated to the a-rhamnal glycoside 17 in 72% yield (at 70% conversion) using benzoyl rhamnal (16) as the glycoside donor and scandium triflate as the promotor. The silyl group at C-3 of the aglycone was then transformed into a hydroxyl group. Zemplén deacylation and photooxidation of the benzylic position at C-1 then converted the two diastereoisomers into the natural product 3 and the C-3 diastereoisomer 20. At this stage the diastereomers 3 and 20 were separated. Alternatively and more easily, the diastereomers were separated at the stage of the urdamycinone B analogues 21a and 21b, followed by a similar reaction sequence to the natural disaccharide 3.

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“…The less polar compound was identical in all respects with a sample kindly provided by Prof. J. Rohr. [32] NMR data of 3: 588 Krohn, Agocs, and Bäuerlein…”

Section: Diacetate 14mentioning

confidence: 99%

mentioning

confidence: 99%

Total Synthesis of Angucyclines. XVII. First Synthesis of Antibiotic 100‐1, a Deoxydisaccharide Angucycline Antibiotic of the Urdamycinone B‐Type

Krohn

Agócs

Bäuerlein

2003

Journal of Carbohydrate Chemistry

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“…This is exemplified by the synthesis of Pgalactosyl-, P-glucosyl-, and P-glucuronyl linkages [ 14e, 16,17,21,26,301. Fucosyl phosphites behave differently under these conditions, however, and a-selectivity is predominant [21,30,311.…”

Section: Low Temperature-dependent Stereoselectivitymentioning

confidence: 99%

“…In the glycosylation of 2-deoxy glycosyl phosphites under TMSOTf activation [12,131, the Hashimoto group [26] recently found that the reaction temperature is crucially important in the control of P-selectivity (see Figure 14, entries 1-3). The selectivities were not significantly affected by the reactivities of the glycosyl donors (entries 1, 4, and 5; a : P = 10: 90, 13 : 87, and 14: 86, respectively).…”

Section: Glycosylation With 2-deoxy Glycosyl Phosphitesmentioning

confidence: 99%

Glycosylation Methods: Use of Phosphites

Zhang

Wong

2000

Carbohydrates in Chemistry and Biology

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In the chemical synthesis of oligosaccharides, the overall procedure can be divided into five steps: 1) design and preparation of the building blocks (glycosyl donors and acceptors) 2) manipulation of the protecting groups to free the desired hydroxyl group; 3) separation of products after each step; 4) stereo-controlled glycosylation; and 5 ) deprotection and product purification. with selected protecting groups;Of those steps, 1-3 are the most time-consuming. Considerable efforts have thus been made to facilitate the synthetic process. For example, many methods have been developed to reduce the number of steps in the synthesis of building blocks. Recently developed orthogonal protection-deprotection strategies [ 1, 21 provide the efficiency and flexibility for the preparation of highly diversified carbohydrate libraries [ 1, 31. To minimize protecting group manipulation, the armed-disarmed strategy [4], the orthogonal glycosylation strategy [ 5 ] , and the one-pot multiglycosylation strategy [6-81 have been developed. In terms of simplifying the purification procedure, solid-phase synthesis [ 91 and one-pot solution-phase synthesis [7d, 81 have shown great promise.Glycosylation is the central reaction of carbohydrate chemistry. Because low yield, low regioselectivity, and low stereoselectivity are frequently encountered, it is this step which requires special attention. Though chemists might be able to synthesize any oligosaccharide [lo], there is no universally employed glycosylation [ lOc, 111. Therefore, development of new and efficient methods of glycosylation is still quite challeng,ing.Carbohydrates in Chemistry and Biology

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“…1) (8). Over the past two decades, we have been concerned with the development of novel stereocontrolled glycosidation reactions capitalizing on phosphorus-containing leaving groups (9)(10)(11)(12)(13)(14). (31).…”

Section: A Introductionmentioning

confidence: 99%

Stereocontrolled Construction of 1,2-cis-α-Glycosidic Linkages Using Glycosyl Diphenyl Phosphates and Synthesis of α-Galactosylceramide KRN7000

Nambu

Nakamura

Suzuki

et al. 2010

TIGG

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The development of a general stereoselective method for 1,2-cis-α-glycosidations remains an important issue for synthesis in carbohydrate chemistry. Recently, we have achieved a highly stereocontrolled construction of 1,2-cis-α-glycosidic linkages using glycosyl diphenyl phosphates as glycosyl donors. The per-O-benzyl-protected glucosyl and galactosyl donors and the 3,4,6-tri-O-acetyl-2-azido-2-deoxygalactosyl donor each react with a range of acceptor alcohols in the presence of 0.05-0.2 equiv of HClO 4 in dioxane/Et 2 O (1:1) to afford glycosides in good yields with good to high α-selectivities. The synthetic utility of the present glycosidation method was demonstrated by a stereoselective synthesis of the α-galactosylceramide KRN7000, an activator of natural killer (NK) T cells through CD1d molecules.

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An Attempt at the Direct Construction of 2-Deoxy-β-glycosidic Linkages Capitalizing on 2-Deoxyglycopyranosyl Diethyl Phosphites as Glycosyl Donors

Cited by 70 publications

References 0 publications

Total Synthesis of Angucyclines. XVII. First Synthesis of Antibiotic 100‐1, a Deoxydisaccharide Angucycline Antibiotic of the Urdamycinone B‐Type

Total Synthesis of Angucyclines. XVII. First Synthesis of Antibiotic 100‐1, a Deoxydisaccharide Angucycline Antibiotic of the Urdamycinone B‐Type

Glycosylation Methods: Use of Phosphites

Stereocontrolled Construction of 1,2-cis-α-Glycosidic Linkages Using Glycosyl Diphenyl Phosphates and Synthesis of α-Galactosylceramide KRN7000

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