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

An Ir-catalyzed reductive formation of functionalized nitrones from N-hydroxyamides was reported. The reaction took place through two types of iridium-catalyzed reactions including dehydrosilylation and hydrosilylation. The method showed high chemoselectivity in the presence of sensitive functional groups, such as methyl esters, and was successfully applied to the synthesis of cyclic and macrocyclic nitrones, which are known to be challenging compounds to access by conventional methods. 1H NMR studies strongly supported generation of an N-siloxyamide and an N,O-acetal as the actual intermediates.

An Iridium-Catalyzed Reductive Approach to Nitrones from N-Hydroxyamides

Nucleophilic addition to amides has been recognized as a promising transformation for total synthesis of complex alkaloids. Amides can accept two different organometallic reagents through the nucleophilic addition, which enables it to serve as a stable surrogate of multi-substituted amines. However, the nucleophilic addition has been overlooked for a long time due to three main reasons: low electrophilicity of amide carbonyls, potential hydrolysis of the reaction intermediate and excess addition of an organometallic reagent. This mini review focuses on the recent progress of total synthesis of complex alkaloids based on the nucleophilic additions to N-alkoxyamides, tertiary amides and secondary amides.

Total synthesis of complex alkaloids by nucleophilic addition to amides.

Recent developments in β-C-glycosides: synthesis and applications

Being an attractive class of naturally occurring molecules with fascinating properties sugars and their derivatives have wide applications in different fields especially in drug discovery. Due to their highly diverse nature they play various important key roles in biological systems. In terms of providing both desirable structural diversity and compound libraries, multicomponent reactions (MCRs) are most efficient strategies. MCRs are widely employed by chemists to generate sugar based derivatives with significantly extended variations having various benefits to society. The advances in the synthesis of structurally diversified sugar based derivatives through new MCRs of the previous decade are reviewed.

Recent advances in multicomponent reactions involving carbohydrates

A direct approach to the synthesis of polyhydroxylated piperidine and pyrrolidine peptidomimetics is described. The presented strategy is based on one-pot reduction of sugar-derived lactams with Schwartz’s reagent followed by a multicomponent Ugi–Joullie reaction.

Synthesis of polyhydroxylated piperidine and pyrrolidine peptidomimetics via one-pot sequential lactam reduction/Joullié-Ugi reaction.

A direct approach to the synthesis of indolizidine and quinolizidine scaffolds of iminosugars is described. The presented strategy is based on a one-pot sugar lactam reduction with Schwartz’s reagent followed by a diastereoselective Mannich/Michael tandem reaction of the resulting sugar imine with Danishefsky’s diene. The stereochemical course of the investigated reaction has been explained in detail. The obtained bicyclic products are attractive building blocks for the synthesis of various naturally occurring polyhydroxylated alkaloids and their derivatives.

Synthesis of polyhydroxylated quinolizidine and indolizidine scaffolds from sugar-derived lactams via a one-pot reduction/Mannich/Michael sequence.

Acid catalyzed rearrangement of vinyl and ketene acetals

A new synthesis of highly functionalized cyclohexenes via a vinylogous Ferrier-Petasis cyclization reaction

Substituted vinyl and ketene acetals undergo smooth oxygen-to-carbon rearrangement with a catalytic amount of TMSOTf to afford chain-extended ketones or esters, respectively. The developed procedure has been applied to the stereoselective synthesis of C -glycosides from the corresponding anomeric vinyl ethers.

Elżbieta Maziarz

Papers

Synthesis of polyhydroxylated piperidine and pyrrolidine peptidomimetics via one-pot sequential lactam reduction/Joullié-Ugi reaction.

Synthesis of polyhydroxylated quinolizidine and indolizidine scaffolds from sugar-derived lactams via a one-pot reduction/Mannich/Michael sequence.

Acid catalyzed rearrangement of vinyl and ketene acetals

A new synthesis of highly functionalized cyclohexenes via a vinylogous Ferrier-Petasis cyclization reaction

Acid Catalyzed Rearrangement of Vinyl and Ketene Acetals.