Sub-stoichiometric reductive etherification of carbohydrate substrates and one-pot protecting group manipulation

Chen, Chiao Wen; Wang, Ching Chi; Li, Xin Ru; Witek, Henryk A.; Mong, Kwok Kong Tony

doi:10.1039/d0ob00252f

Cited by 6 publications

(8 citation statements)

References 31 publications

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“…The conversion of 33 to desired D,D-Hep-IV donor 31 was achieved via (i) the dibutyltin oxide mediated benzylation at C7 hydroxyl, and (ii) sequential trimethylsilylation and reductive etherification with benzaldehyde (PhCHO) at C6 hydroxyl. [46] Having prepared the D,D-and L,D-Hep donors and acceptors 31, 12, 5, and 32, we proceeded to the synthesis of inner core tetrasacharide 29. Prior to the one-pot reaction, some efforts were required to optimize the stoiciometric amounts of the glycosyl components in each glycosylation steps (unpublished data).…”

Section: Resultsmentioning

confidence: 99%

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Cheng

Wang

et al. 2023

Chemistry An Asian Journal

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We report a practical one-pot glycosylation strategy for synthesis of bacterial inner core oligosaccharides that composed of unavailable L-glycero-D-manno and D-glycero-Dmanno-heptopyranose components. The glycosylation method features a new orthogonal glycosylation procedure; whereby a phosphate acceptor is coupled with a thioglycosyl donor producing a disaccharide phosphate, which can be engaged in another orthogonal glycosylation procedure to couple with a thioglycosyl acceptor. The phosphate acceptors used in above one-pot procedure are directly prepared from thioglycosyl acceptors via the in-situ phosphorylation. Such phosphate acceptor preparation protocol eliminates the traditional protection and deprotection procedures. Based on the new one-pot glycosylation strategy, two partial inner core structures of Yersinia pestis lipopolysaccharide and Haemophilus ducreyi lipooligosaccharide were acquired.

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Section: Resultsmentioning

confidence: 99%

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Cheng

Wang

et al. 2023

Chemistry An Asian Journal

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“…Finally, two examples of this reductive transformation were presented last year. On the one hand, Mong and co‐workers designed a general procedure for the reductive etherification of different trimethylsilyl‐protected glycosides or polyols with benzaldehyde or 2‐naphthylaldehyde using PMHS as hydride source and TMS−OTf as catalyst (entry 17) [67] . By applying this methodology sequentially, several TMS‐protected substrates prepared by alcohol silylation without isolation [53c] can be converted to the corresponding benzyl and naphthylmethyl ethers avoiding common transilylation side reactions [67] .…”

Section: Reductive Etherification Of Alcohols or Surrogates With Aldehydes/ketonesmentioning

confidence: 99%

“… [67] By applying this methodology sequentially, several TMS‐protected substrates prepared by alcohol silylation without isolation [53c] can be converted to the corresponding benzyl and naphthylmethyl ethers avoiding common transilylation side reactions. [67] On the other hand, Fritz‐Langhals et al. synthesized a novel cationic germanium complex [Cp*Ge]B(Ar F ) 4 able to catalyze the reductive coupling between ethoxytrimethylsilyl and hexanal in the presence of triethylsilane as reductor (entry 18).…”

Section: Reductive Etherification Of Alcohols or Surrogates With Aldehydes/ketonesmentioning

confidence: 99%

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO₂ and Related Transformations for the Synthesis of Ether Derivatives

et al. 2021

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Ether derivatives have myriad applications in several areas of chemical industry and academia. Hence, the development of more effective and sustainable protocols for their production is highly desired. Among the different methodologies reported for ether synthesis, catalytic reductive alcohol etherifications with carbonyl‐based moieties (aldehydes/ketones and carboxylic acid derivatives) have emerged in the last years as a potential tool. These processes constitute appealing routes for the selective production of both symmetrical and asymmetrical ethers (including O‐heterocycles) with an increased molecular complexity. Likewise, ester‐to‐ether catalytic reductions and hydrogenative alcohol etherifications with CO2 to dialkoxymethanes and other acetals, albeit in less extent, have undergone important advances, too. In this Review, an update of the recent progresses in the area of catalytic reductive alcohol etherifications using carbonyl‐based compounds and CO2 have been described with a special focus on organic synthetic applications and catalyst design. Complementarily, recent progress made in catalytic acetal/ketal‐to‐ether or ester‐to‐ether reductions and other related transformations have been also summarized.

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“…While the preparation of this manuscript was in progress, Mong and co-workers reported a reductive etherification in glucosamine protection using polymethylhydrosiloxane as the reducing source. [37] The selectivity of reduction is important in a one-pot reaction, which needs to distinguish between acetal protection and reductive etherification.…”

Section: Scheme 6 Formal Synthesis Of Lipid a 13mentioning

confidence: 99%

One‐Pot Protection Strategy of Glucosamine to Assemble Building Blocks of Chitosan and Lipid A

et al. 2020

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This investigation describes a one‐pot reaction to prepare a series of building blocks for glycosylation reactions, such as 3‐alcohol glucosamines, fully protected glucosamines, O‐4 and O‐6 alcohol glucosamines. These reactions readily produce not only glycosyl donors and acceptors, but also different glycosyl units that can be changed based on the needs of the experiment. The synthesis of some molecules containing glucosamines, including saccharide chains of glycopeptide (GP) and precursors of lipid A disaccharide backbone, are also described. GP has good selectivity for tumor angiogenesis and this phenomenon makes the GP a potential target drug. Lipid A has recently been adopted as an adjuvant for human vaccines.

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Sub-stoichiometric reductive etherification of carbohydrate substrates and one-pot protecting group manipulation

Abstract: Polymethylhydrosiloxane (PMHS): a sub-stoichiometric reducing agent for reductive etherification of carbohydrate substrates and its application for one-pot protecting group manipulation

Cited by 6 publications

References 31 publications

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO₂ and Related Transformations for the Synthesis of Ether Derivatives

One‐Pot Protection Strategy of Glucosamine to Assemble Building Blocks of Chitosan and Lipid A

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Sub-stoichiometric reductive etherification of carbohydrate substrates and one-pot protecting group manipulation

Abstract: Polymethylhydrosiloxane (PMHS): a sub-stoichiometric reducing agent for reductive etherification of carbohydrate substrates and its application for one-pot protecting group manipulation

Cited by 6 publications

References 31 publications

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO2 and Related Transformations for the Synthesis of Ether Derivatives

One‐Pot Protection Strategy of Glucosamine to Assemble Building Blocks of Chitosan and Lipid A

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Catalytic Reductive Alcohol Etherifications with Carbonyl‐Based Compounds or CO₂ and Related Transformations for the Synthesis of Ether Derivatives