Its even more than a centennial that the systematic researches of chemical alteration of sugars have been advancing. Out of all the interest in the field of N‐glycoside has assembled pace over the past few years. Therefore, N‐functionalization of sugar is one of the most fundamental modifications along with other group like azide, amide etc also play a remarkable role in the field of glycoscience. Different approaches to access structurally modified N‐glycosides in carbohydrate derivatives are reviewed. The goal of this review is to provide an overview of different way of N‐functionalization of amino sugar and induction of nitrogen scaffolds for the synthesis of various orthogonal protective groups of the N‐glycoside. The N‐functionalization of sugars designate as follows: (a) glycosylamine, (b) glycosyl azide, and (c) introduction of N‐functionality to the sugar for formation of N‐glycosides. This is the first review focus on N‐functionalization of sugars which will be a future scope that influence the readers to work in this area further.

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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Trichloroisocyanuric acid (TCCA), a readily accessible, inexpensive, shelf-stable, and non-toxic reagent in combination with PPh 3 , has been used for dehydrative glycosylation reactions with furanose, pyranose, and deoxysugar hemiacetals. The methodology provides a mild reaction condition, good functional group tolerance, featuring a wide variety of substrate scope using O-, C-, N-, and S-based nucleophiles with good to excellent yields and majority αselectivity in case of O-glycosides while the stereoselectivity in case of C-, N-and S-glycosides depends upon the nature of nucleophiles. Notably, this mild dehydrative glycosylation system also provides a reliable method for the synthesis of challenging phenolic glycosides. The progress of the dehydrative glycosylation reaction was monitored by mass and NMR spectroscopy and it is hypothesized that alkoxyphosphonium ions might be the reactive intermediate formed in this process, supported by 31 P nuclear magnetic resonance studies.

A catalyst-, metal-and base-free unprecedented one-pot multicomponent synthetic strategy has been established for the construction of various substituted morpholine glycoconjugates through four-component reactions of glycosyl amino alcohol, chloroacetone, acid, and isocyanides. Unexpectedly, this one-pot approach generates only the cyclized morpholine scaffolds rather than normal Ugi adduct without any external base. This reaction proceeds via in situ formations of Schiff-base followed by an intramolecular halogen displacement process, finally the Joullie-Ugi reaction takes place leading to the corresponding products with a mixture of diastereomers.