[asa] My Brain Hurts

This week's *Nature* has a special section on glycochemistry and
glycobiology<http://www.nature.com/nature/supplements/insights/glycobiology/index.html>.
The lead editorial starts with:

Carbohydrates have long been underappreciated by the scientific community,
> and many scientists approach the complex structures and *elaborate
> nomenclature of carbohydrates with trepidation*.

If you don't believe them check this out:

In addition to carbohydrate donors with anomeric heteroatom derivatives, the
> use of glycals (12, Fig. 1c) as glycosyl donors has been explored
> extensively in complex carbohydrate synthesis. The presence of the
> 1,2-alkene functionality in this substrate allows the use of various
> electrophilic oxidants (El+) that are reactive to enol ether nucleophiles
> (12). The resulting activated glycosyl donor 13 is then poised to receive an
> appropriate nucleophilic glycosyl acceptor (Nu–H) to form the glycoconjugate
> 14. These methods allow the introduction of various functionalities 'Z' at
> the C2-position in conjunction with anomeric bond formation. For example,
> C2-oxygen transfer to glycal donors has proved useful, involving
> dimethyldioxirane (DMDO)-mediated33 or sulphonium-mediated34 1,2-epoxidation
> of glycals, followed by anomeric substitution, to generate C2-hydroxy
> glycosides (15, Fig. 1d). Similarly, I(III)-containing reagents have
> recently been applied to the generation of selectively protected
> C2-acyloxyglycosides (16)35. The synthesis of 2-amino-2-deoxyglycosides has
> drawn considerable attention owing to the abundance and importance of this
> class of glycoside in naturally occurring glycoconjugates. The venerable
> C2-azidonitration reaction of glycals36 to afford C2-azido pyranose
> derivatives (17) has been, and continues to be, a favoured method by which
> to introduce the C2-N-functionality. Other reactions have subsequently been
> developed for C2-nitrogen transfer onto the glycal donor, including
> stereoselective installation of a sulphonamide group (for instance, 18, by
> iodosulphonamido glycosylation)33, as well as less-used protocols to install
> a C2-carbamate functionality37 and the naturally occurring C2-acetamido
> group38.
>

All I can say is Terry, enjoy. Yes, I know you're a protein guy but at least
you have a leg up on the rest of us. I'm getting an ice pack.

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Received on Thu Apr 26 16:06:46 2007