Anomeric-oxygen activation for glycoside synthesis: the trichloroacetimidate method.

Preface. Contributors. Solid--Phase Carbohydrate Synthesis: The Early Work (W.--C. Haase & P. Seeberger). The Glycal Assembly Method on Solid Supports: Synthesis of Oligosaccharides and Glycoconjugates (P. Cirillo & S. Danishefsky). The Sulfoxide Glycosylation Method and its Application to Solid--Phase Oligosaccharide Synthesis and the Generation of Combinatorial Libraries (C. Taylor). The Use of O--Glycosyl Trichloroacetimidates for the Polymer--Supported Synthesis of Oligosaccharides (L. Knerr & R. Schmidt). Synthesis of Oligosaccharides on Solid Support Using Thioglycosides and Pentenyl Glycosides (V. Wittmann). Solid--Phase Oligosaccharide Synthesis Using Glycosyl Phosphates (W.--C. Haase, et al.). Stereoselective beta--Mannosylation on Polymer Support (Y. Ito & H. Ando). Tools for "On--Bead" Monitoring and Analysis in Solid--Phase Oligosaccharide Synthesis (W.--C. Haase, et al.). Polyethyleneglycol omega--Monomethylether (MPEG)--Supported Solution--Phase Synthesis of Oligosaccharides (J. Krepinsky & S. Douglas). Two--Direction Glycosylations for the Preparation of Libraries of Oligosaccharides (G.--J. Boons & T. Zhu). Carbohydrate Libraries in Solution Using Thioglycosides: From Multistep Synthesis to Programmable, One--Pot Synthesis (E. Simanek & C.--H. Wong). Carbohydrate Libraries by the Random Glycosylation Approach (O. Kanie & O. Hindsgaul). Solid--Phase Synthesis of Biologically Important Glycopeptides (N. Bezay & H. Kunz). Preparation and Screening of Glycopeptide Libraries (P. St. Hilaire, et al.). Index.

Solid-phase oligosaccharide synthesis and combinatorial carbohydrate libraries.

The mechanisms of T cell help for production of antilipid antibodies are largely unknown. This study shows that invariant NK T cells (iNK T cells) and B cells cooperate in a model of antilipid antigen-specific antibody responses. We use a model haptenated lipid molecule, 4-hydroxy-3-nitrophenyl-αGalactosylCeramide (NP-αGalCer), to demonstrate that iNK T cells provide cognate help to lipid-antigen-presenting B cells. B cells proliferate and IgG anti-NP is produced from in vivo-immunized mice and in vitro cocultures of B and NK T cells after exposure to NP-αGalCer, but not closely related control glycolipids. This B cell response is absent in CD1d−/− and Jα18−/− mice but not CD4−/− mice. The antibody response to NP-αGalCer is dominated by the IgM, IgG3, and IgG2c isotypes, and marginal zone B cells stimulate better in vitro lipid antigen-driven proliferation than follicular B cells, suggesting an important role for this B cell subset. iNK T cell help for B cells is shown to involve cognate help from CD1d-instructed lipid-specific iNK T cells, with help provided via CD40L, B7–1/B7–2, and IFN-γ, but not IL-4. This model provides evidence of iNK T cell help for antilipid antibody production, an important aspect of infections, autoimmune diseases, and vaccine development. Our findings also now allow prediction of those microbial antigens that would be expected to elicit cognate iNKT cell help for antibody production, namely those that can stimulate iNKT cells and at the same time have a polar moiety that can be recognized by antibodies.

NK T cells provide lipid antigen-specific cognate help for B cells

Deoxy-sugars often play a critical role in modulating the potency of many bioactive natural products. Accordingly, there has been sustained interest in methods for their synthesis over the past several decades. The focus of much of this work has been on developing new glycosylation reactions that permit the mild and selective construction of deoxyglycosides. This Review covers classical approaches to deoxyglycoside synthesis, as well as more recently developed chemistry that aims to control the selectivity of the reaction through rational design of the promoter. Where relevant, the application of this chemistry to natural product synthesis will also be described.

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Michel Trumtel

Papers

Preparation of pyranoid glycal derivatives from phenyl thioglycosides and glycosyl phenyl sulphones

The synthesis of 2′-deoxy-β-disaccharides: Novel approaches

An easy synthesis of 2′-deoxy-β-disaccharides☆

Convenient syntheses of substituted pyranoid glycals from thiophenyl glycosides and glycosyl phenylsulfones

Syntheses of trisaccharide C-D-E and tetrasaccharide B-C-D-E fragments found in orthosomycins.