Claisen rearrangement over the past nine decades.

Advances in the chemical synthesis of C-pyranosides/furanosides are summarized, covering the literature from 2000 to 2016. The majority of the methods take advantage of the construction of the glycosidic C—C bond. These C-glycosylation methods are categorized herein in terms of the glycosyl donor precursors, which are commonly used in O-glycoside synthesis and are easily accessible to nonspecialists. They include glycosyl halides, glycals, sugar acetates, sugar lactols, sugar lactones, 1,2-anhydro sugars, thioglycosides/sulfoxides/sulfones, selenoglycosides/telluroglycosides, methyl glycosides, and glycosyl imidates/phosphates. Mechanistically, C-glycosylation reactions can involve glycosyl electrophilic/cationic species, anionic species, radical species, or transition-metal complexes, which are discussed as subcategories under each type of sugar precursor. Moreover, intramolecular rearrangements, such as the Claisen rearrangement, Ramberg–Backlund rearrangement, and 1,2-Wittig rearrangement, which usuall...

Recent Advances in the Chemical Synthesis of C-Glycosides

Catalysis of the Claisen rearrangement

Chlorination−elimination chemistry coupled with three-component Joullie−Ugi reaction and facile deprotection allowed efficient access to an array of polyhydroxylated pyrrolidines through parallel synthesis that may be considered to be a library of imino (aza) sugars (glycomimetics) and/or dihydroxyprolyl peptides (peptidomimetics). The utility of generating such a library was illustrated by screening against 15 different targets that revealed potent and selective inhibition of the Gaucher's disease glycosyltransferase enzyme glucosylceramide synthase and of primary pathogen model for human hepatitis C virus (HCV) and bovine diarrhoeal virus (BVDV). An observed selectivity for this HCV model over hepatitis B virus and remarkably low toxicity suggest a novel mode of action.

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Glyco- and peptidomimetics from three-component Joullié-Ugi coupling show selective antiviral activity.

http://web4.uwindsor.ca/users/j/jlichaa/reference.nsf/0/10ff8b04ff3a317885256d88005720f6/$FILE/jcsp1-2002-2763-ti-alkylidene.pdf

Titanium reagents for the alkylidenation of carboxylic acid and carbonic acid derivatives

Stereoselective synthesis of C-glycosides via Tebbe methylenation and Claisen rearrangement

A variety of β- or α-C-glycosides may be readily accessed in an entirely stereoselective fashion from esters derived from the reaction of carboxylic acids and 3-hydroxy glycals, by way of a tandem reaction sequence of Tebbe methylenation and Claisen rearrangement. Though of wide scope, for example allowing the synthesis of 1–6 linked C-disaccharides, the methodology does not currently allow the synthesis of C-glycosyl α-amino acids.

Stereoselective synthesis of C-glycosides from carboxylic acids: the tandem Tebbe–Claisen approach

Synthesis of α-C-glycosides via tandem Tebbe methylenation and Claisen rearrangement

A variety of β- C -glycosides may be readily accessed in a stereoselective fashion from 3-OH glycal esters, via the use of Tebbe methylenation and subsequent thermal Claisen rearrangement. The use of carbohydrate ester substrates allows the formation of β(1→6) linked C -disaccharides.

H. Yasmin Godage

Papers

Stereoselective synthesis of C-glycosides via Tebbe methylenation and Claisen rearrangement

Stereoselective synthesis of C-glycosides from carboxylic acids: the tandem Tebbe–Claisen approach

Synthesis of α-C-glycosides via tandem Tebbe methylenation and Claisen rearrangement

Stereoselective Synthesis of C-Glycosides via Tebbe Methylenation and Claisen Rearrangement.

Stereoselective Synthesis of C‐Glycosides from Carboxylic Acids: The Tandem Tebbe—Claisen Approach.