Novel 1,2- cis -stereoselective glycosylations utilizing organoboron reagents and their application to natural products and complex oligosaccharide synthesis

Takahashi, Daisuke; Tanaka, Masamichi; Nishi, Nobuya; Toshima, Kazunobu

doi:10.1016/j.carres.2017.10.004

Cited by 32 publications

(3 citation statements)

References 63 publications

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“…In contrast, the construction of our desired 1,2- ci s α- O -glucoside is much more challenging. It requires glycosyl donors having nonassisting functionality at C-2 position, and even so, the reaction normally produces a mixture of α and β isomers [ 30 , 31 , 32 ]. In this work, we chose 2,3,4,6-tetra- O -benzyl-glucopyranosyl trichloroacetimidate 6 as the glucosyl donor, which was synthesized from 2,3,4,6-tetra- O -benzyl glucose with trichloroacetonitrile in dichloromethane (DCM) using anhydrous potassium carbonate as catalysis (98% yield, α:β ≈ 1:4) [ 33 , 34 ].…”

Section: Resultsmentioning

confidence: 99%

First Total Synthesis of 5′-O-α-d-Glucopyranosyl Tubercidin

Ouyang¹,

Huang²,

Yang³

et al. 2020

Marine Drugs

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The first total synthesis of 5′-O-α-d-glucopyranosyl tubercidin was successfully developed. It is a structurally unique disaccharide 7-deazapurine nucleoside exhibiting fungicidal activity, and was isolated from blue-green algae. The total synthesis was accomplished in eight steps with 27% overall yield from commercially available 1-O-acetyl-2,3,5-tri-O-benzoyl-β-d-ribose. The key step involves stereoselective α-O-glycosylation of the corresponding 7-bromo-6-chloro-2′,3′-O-isopropylidene-β-d-tubercidin with 2,3,4,6-tetra-O-benzyl-glucopyranosyl trichloroacetimidate. All spectra are in accordance with the reported data for natural 5′-O-α-d-glucopyranosyl tubercidin. Meanwhile, 5′-O-β-d-glucopyranosyl tubercidin was also prepared using the same strategy.

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Section: Resultsmentioning

confidence: 99%

First Total Synthesis of 5′-O-α-d-Glucopyranosyl Tubercidin

Ouyang¹,

Huang²,

Yang³

et al. 2020

Marine Drugs

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“…There is brief literature on protecting groups and from the last couple of years, a wide variety of protecting groups was revealed and successfully used to grant the stereoselective formation of both 1,2-cis-and 1,2-trans-linked complex oligosaccharides. [9] To date, several reviews on stereoselective glycosylation [10][11][12][13][14][15][16][17][18] were reported and also there is a rich literature available on the influence of the protecting groups [19][20][21] on stereoselectivity which have been also reviewed from time to time. Out of all, picolinyl (Pic) [22] and picoloyl (Pico) [22a,23] are emerges out as the most useful and efficient protecting group, as it can be used for the formation of both either stereoselectively α-glycoside or β-glycoside depending upon its position of substitution.…”

Section: Introductionmentioning

confidence: 99%

Influence of Remote Picolinyl and Picoloyl Stereodirecting Groups for the Stereoselective Glycosylation

Khanam

Mandal

2020

Asian J Org Chem

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Sugar compounds generally consist of several hydroxyl groups, responsible for the generation of complex oligosaccharides and are discriminated against or manipulated by using protecting groups. The protecting groups in carbohydrate chemistry adopt a central position in controlling stereoselectivity of glycosylation reaction. In all, picoloyl (Pico) and picolinyl (Pic) group are scrutinize as admirable protecting groups for the evaluation of efficient and convenient glycosyl donors which in turn, synthesize both 1,2‐cis‐ and 1,2‐trans‐linked complex and challenging oligosaccharides stereoselectively either through hydrogen bond mediated aglycone delivery (HAD) or by neighbouring group participation. This review explores the recent advances in the use of picoloyl (Pico) and picolinyl (Pic) as stereo‐directing groups for high facial α‐ or β‐stereoselectivity and its applications in the synthesis of biologically important oligosaccharides.

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“…Recently, Takemoto developed the regio- and stereoselective synthesis of 1,2- cis -glycosyides based on the catalytic activation of 1,2-dihydoroxyglycosyl acceptors using cyclic diarylborinic acid. In connection with glycosylation via a tetracoordinated boronate intermediate, the Toshima and Takahashi group reported systematic studies of the unique 1,2- cis -stereoselective glycosylation of unprotected or partially protected glycosyl acceptors utilizing a 1,2-anhydroglycosyl donor with organoboronic acid catalysts . Most recently, Kusano and co-workers reported that benzoxaborole showed catalytic activity for regioselective Koenigs–Knorr glycosylation (Figure C).…”

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confidence: 99%

Boronic Acid-Catalyzed Regioselective Koenigs–Knorr-Type Glycosylation

et al. 2021

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Boronic acid-catalyzed regioselective Koenigs− Knorr-type glycosylation is presented. The reaction of an unprotected or partially protected glycosyl acceptor with a glycosyl halide donor in the presence of silver oxide and a low catalytic amount of imidazole-containing boronic acid was found to proceed smoothly, which enables construction of a 1,2-trans glycosidic linkage with high regioselectivities. This is the first example of the use of a boronic acid catalyst to initiate regioselective glycosylation via the activation of cis-vicinal diols in glycosyl acceptors. Note pubs.acs.org/joc

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Novel 1,2- cis -stereoselective glycosylations utilizing organoboron reagents and their application to natural products and complex oligosaccharide synthesis

Cited by 32 publications

References 63 publications

First Total Synthesis of 5′-O-α-d-Glucopyranosyl Tubercidin

First Total Synthesis of 5′-O-α-d-Glucopyranosyl Tubercidin

Influence of Remote Picolinyl and Picoloyl Stereodirecting Groups for the Stereoselective Glycosylation

Boronic Acid-Catalyzed Regioselective Koenigs–Knorr-Type Glycosylation

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