A palladium-catalyzed regio- and diastereoselective diarylation of glycals pseudoglycals, which is a kind Heck–Suzuki arylation, described. wide range arylboronic acids reacted under these conditions smoothly. Selectivity was C1–C2(α,α) in the case but C2–C3(β,β) for pseudoglycals. Quantum chemical analysis has been carried out to establish reaction mechanism, may involve Pd(II)/Pd(O). TEMPO plays key role formation diaryl glycoside due its radical nature.

Orthogonally protected monosaccharide building blocks have been prepared using TCT in a one-pot multicomponent transformation. The process involves successive steps of arylidene acetalation, esterification and regioselective reductive acetal cleavage. High regioselectivity, scope for broad range substrates, functional group tolerance, mild reaction conditions, easy handling wide application are few advantages the current process.

A highly stereoselective rapid C-glycosylation reaction has been developed between glycal and unactivated alkynes in the presence of coppertriflate ascorbic acid at low catalyst loading room temperature. wide variety glycals aryl acetylenes participate smoothly. TfOH generated during reduction Cu(OTf)2 by may be active for glycosylation.

Abstract The palladium‐catalyzed stereoselective synthesis of 2,3‐deoxy‐ C ‐aryl glycosides was investigated. strategy is based on the Pd‐catalyzed desulfitative Heck coupling arylsulfonyl chlorides and glycals with good leaving groups. An attempt made to establish reaction mechanism, which may involve Pd II /Pd 0 interconversion under basic conditions.

α-C-arylglycosides can be obtained through the addition of aryl zinc reagents to sugar epoxides. The required nucleophiles easily from corresponding boronic acids by B-Zn exchange and attack 1,2 epoxides in a highly diastereoselective fashion generate 1,2-cis-α-hexapyranosyl glycosides under ligand- base-free conditions.

A highly regio- and diastereo-selective synthesis of halogenated C-vinyl glycosides has been achieved from glycals unactivated aryl acetylenes in the presence Lewis acids via a tandem glycosylation–halogenation reaction. The acid used served dual purpose activating allylic acetoxy group serving as halogen source for Markovnikov addition across triple bond, which makes process atom economic. synthesized glycosyl vinyl halides have precursors various Pd catalyzed C–C cross coupling reactions.

An efficient strategy for the synthesis of C-2 and C-3 branched sugar dienes via cross dehydrogenative coupling enol ethers with terminal alkenes was developed. Both pyran furan based coupled smoothly electron rich as well deficient alkene sources yielding complete E-stereoselectivity. This reaction applied successfully orthogonally protected pseudo-C-saccharides an alternative to olefin metathesis. Substrate scope further enhanced by reacting exoglycals methyl acrylate generate C-5 sugars...

Perfluorophenylboronic acid <bold>1c</bold> catalyzes the direct stereoselective addition of alcohol nucleophiles to deactivated peracetylated <sc>d</sc>-galactal <bold>2</bold> give 2-deoxygalactosides <bold>4a–o</bold>, <bold>6a–11a</bold> in 55–88% yield with complete α-selectivity.

Zinc mediated alkynylation reaction was studied for the preparation of C-glycosides from unactivated alkynes. Different glycosyl donors such as glycals and anomeric acetates were tested towards an alkynyl zinc reagent obtained alkynes using dust ethyl bromoacetate additive. The method provides simple, mild stereoselective access to glycosides both aromatic aliphatic acetylenes.

Sugar enol ethers undergo efficient coupling at C-2 with unactivated cycloalkenes under a low Pd loading affording allylic substitution products. High diastereoselectivity was observed the centre sterically hindered substrates. Generation of π-allyl complex by Pd(ii) catalyst via cleavage C-H bond cycloalkene may be responsible for formation sp2-sp3

A practical three-component reaction between unactivated carbohydrates, oxoacetonitriles, and ammonium acetate gave densely functionalized pyrroles in 75–96% yields. Disaccharides afforded novel pyrrolo-glycosides. This metal-free, Et3N-catalyzed cascade proceeded with exclusive chemo-, regio-, stereoselectivities showed a wide substrate scope high atom economy. It also successfully at 2 g scale, demonstrating potential for large-scale synthesis. The functional groups on the permit easy...

A mild and convenient method for the synthesis of α‐glycosyl chlorides in high 80–96 % yields within 15–30 min using 2‐chloro‐1,3‐dimethylimidazolinium chloride (DMC) is disclosed. The has a wide substrate scope compatible with labile OH protecting groups, including benzyl, acetyl, benzoyl, isopropylidene, benzylidene, TBDMS ( tert ‐butyldimethylsilyl), TBDPS ‐butyldiphenylsilyl) groups. excellent α selectivity obtained this reaction attributed to in‐situ isomerization β‐glycosyl more stable...

<italic>C</italic>-Glycosidation plays a significant role in the synthesis of optically active scaffolds.

Abstract A diastereoselective, metal‐free, one‐pot domino synthetic strategy was developed for the transformation of glycals into new chiral scaffolds. Optimization reaction conditions to exclude normal Ferrier products, characterization entities, and a plausible mechanism were investigated.

A convenient protocol was developed for the synthesis of 2,3-unsaturated C-, O-, N- and S-linked glycosides (enosides) using 20 mol % perflurophenylboronic acid catalyst via Ferrier rearrangement. Using this protocol, D-glucals L-rhamnals reacted with various S-nucleophiles to give a wide range in up 98% yields mainly α-anomeric selectivity. The successfully catalyzed substrates (both glucals nucleophiles) under very mild reaction conditions.

Triflic acid catalyzed cascade stereoselective reaction of glycals with styrenes delivers complex oxabicyclic scaffolds such as cis-oxadecalins or cis-cyclopentanofurans simply by tweaking the solvent. In presence participating solvents like benzene/toluene, Ferrier C-glycosylation and double Friedel–Crafts leads to densely chiral benzo-fused oxadecalins, whereas in DCM, an unprecedented ring-opening, ring-closing sequence generated cis-cyclopentanofurans. An attempt has been made explain...

Isoselenocyanates are valuable coupling partners required for preparing key chemical intermediates and biologically active molecules in an accelerated effective way. Likewise, (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides have been employed numerous one-step heteroannulation reactions to assemble the structural core of several various kinds heterocyclic compounds. Here, we describe inverse electron demand 1,3-dipolar cycloaddition reaction isoselenocyanates with a variety substituted...

A simple trimethylsilyl trifluoromethanesulfonate (TMSOTf)-promoted intermolecular cascade reaction of aromatic diazo ketones with olefins has been developed. This method directly gave 3-phenylethylideneoxindoles from 3-diazooxindoles and styrenes exclusive regioselectivity, chemoselectivity, E-stereoselectivity. The key to the success higher yields is elegant use TMSOTf, which gradually released active triflic acid promoter in situ. tolerates a wide substrate scope electron-donating...

A simple and environment-friendly citric acid-mediated synthesis of glycosides has been reported using Ferrier-rearrangement. Using this protocol, several including pseudo disaccharides was prepared. Citric acid successfully employed for the from D-glucal, L-rhamnal, D-xylal D-galactal with various alcohols to give a broad range in up 80% yields α-isomer as major product under mild reaction conditions.

Abstract We report a strategy for the stereoselective synthesis of 1,2-trans-glycosides in absence neighboring group participation. The present protocol selective glycosylation mainly relies on catalyst control rather than protecting selection. By using this protocol, several glycosides were prepared. Zinc acetate was found to be optimal catalyst, providing desired from glucose- and mannose-derived glycosyl halides at room temperature instead low-temperature conditions.