A simple, mild, and regioselective method for the benzylation of carbohydrate derivatives promoted by silver carbonate

Malik, Satish; Dixit, Vaibhav A.; Bharatam, Prasad V.; Kartha, K. P. Ravindranathan

doi:10.1016/j.carres.2009.12.012

Cited by 33 publications

(17 citation statements)

References 38 publications

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“…Upon treatment with NaH and NiCl 2 , 4,6- O -benzylidene-protected gluco- and galactopyranosides underwent alkylation at the 2-OH and 3-OH groups, respectively, another illustration of the selective functionalization of an equatorial substituent adjacent to an axial position via a chelated intermediate. Silver(I) carbonate has been used to achieve alkylations of furanoside and pyranoside derivatives with BnBr and PMBCl . These reactions appear to be under steric control, perhaps due to the deprotonation of the carbohydrate substrate at the surface of the insoluble promoter.…”

Section: Alkylationmentioning

confidence: 72%

“…Transition metal salts also serve as useful reagents for the selective preparation of ether-protected carbohydrate derivatives (Scheme 79). Complexes of sugars with Cu(II) 250−252 and Ni(II) 254 have been shown to react with alkyl halides in a similar 297 These reactions appear to be under steric control, perhaps due to the deprotonation of the carbohydrate substrate at the surface of the insoluble promoter. The conditions were tolerant of base-labile groups such as esters, which are prone to migration under conventional alkylation conditions.…”

Section: Transition Metal Promoters and Catalystsmentioning

confidence: 99%

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Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

2018

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Methods for site-selective transformations of hydroxyl groups in carbohydrate derivatives are reviewed. The construction of oligosaccharides of defined connectivity hinges on such transformations, which are also needed for the preparation of modified or non-natural sugar derivatives, the installation of naturally occurring postglycosylation modifications, the selective labeling or conjugation of carbohydrate derivatives, and the preparation of therapeutic agents or research tools for glycobiology. The review begins with a discussion of intrinsic factors and processes that can influence selectivity in reactions of unprotected or partially protected carbohydrate derivatives, followed by a description of transformations that engage two OH groups in cyclic adducts (acetals, ketals, boronic esters, and related species). An overview of the various classes of site-selective transformations of OH groups in sugars is then provided: the reactions discussed include esterification, thiocarbonylation, alkylation, glycosylation, arylation, silylation, phosphorylation, sulfonylation, sulfation, and oxidation. Emphasis is placed on recently developed methods that employ reagent or catalyst control to achieve otherwise challenging transformations or site-selectivities.

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Section: Alkylationmentioning

confidence: 72%

Section: Transition Metal Promoters and Catalystsmentioning

confidence: 99%

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

2018

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“…307 In the case of diols, 80% of the primary ether was isolated. The two previous examples are representative of the two approaches.…”

Section: Williamson-type Synthesis Of Glycerol Ethersmentioning

confidence: 99%

Glycerol Ether Synthesis: A Bench Test for Green Chemistry Concepts and Technologies

et al. 2015

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“…The same selectivity as in the stoichiometric methods was observed, but the amount of toxic organotin reagents was reduced to 2-10 mol%. 34,35,38 Metal-and metalloid-mediated protection of glycosides other than tin Other systems for the regioselective protection of diols have been reported based on organoboron, [46][47][48] organosilicon, 49,50 copper(II), [51][52][53][54][55] silver(I), 56 nickel(II) 57 and molybdenum(V) and (II) (Table 2). 58,59 These systems show often a similar selectivity as observed in tin mediated protections.…”

Section: Methodsmentioning

confidence: 99%

“…Other systems for the regioselective protection of diols have been reported based on organoboron, [46][47][48] organosilicon, 49,50 copper(II), [51][52][53][54][55] silver(I), 56 nickel(II) 57 and molybdenum(V) and (II) ( Table 2). 58,59 These systems show often a similar selectivity as observed in tin mediated protections.…”

Section: Tin Mediated Protection Of Glycosidesmentioning

confidence: 99%

Regioselective modification of unprotected glycosides

Jäger

Minnaard

2016

Chem. Commun.

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Selective modification of unprotected carbohydrates is difficult due to the similar reactivity of the hydroxyl groups. In carbohydrate synthesis, therefore, even straightforward transformations often require multiple synthetic steps. The development of selective methods for carbohydrate modification is consequently highly desired. This review describes the methods for the regio- and chemoselective carbohydrate modification, with a focus on novel approaches that mainly apply transition metal catalysis and organocatalysis, and discusses the challenges and opportunities in this field.

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A simple, mild, and regioselective method for the benzylation of carbohydrate derivatives promoted by silver carbonate

Cited by 33 publications

References 38 publications

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives

Glycerol Ether Synthesis: A Bench Test for Green Chemistry Concepts and Technologies

Regioselective modification of unprotected glycosides

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