Synthesis of 1,5-dideoxy-1,5-iminoribitol C-glycosides through a nitrone-olefin cycloaddition domino strategy: identification of pharmacological chaperones of mutant human lysosomal β-galactosidase.

We report herein a newly developed domino reaction that facilitates the synthesis of new 1,5-dideoxy-1,5-iminoribitol iminosugar C-glycosides 7a-e and 8. The key intermediate in this approach is a six-membered cyclic sugar nitrone that is generated in situ and trapped by an alkene dipolarophile via a [2 + 3] cycloaddition reaction to give the corresponding isooxazolidines 10a-e in a "one-pot" protocol. The iminoribitol C-glycosides 7a-e and 8 were found to be modest β-galactosidase (bGal) inhibitors.

Synthesis and conformational study of chiral oxepines: the Baylis-Hillman reaction and RCM approach with sugar aldehyde.

The Baylis-Hillman reaction of 3-O-allyl-alpha-d-xylo-pentodialdo-1,4-furanose 3 afforded a diastereomeric mixture of d-gluco- and l-ido-configured alpha-methylene-beta-hydroxy esters 4a and 4b, respectively, in a ratio of 2:3. Reduction of the ester functionality in 4a/4b gave alcohols 5a/5b. The diene thus formed in 5a/5b was subjected to ring-closing metathesis (Grubbs' second-generation catalyst) to afford oxa-bicyclic ring system 6a/6b in high yield.

Catechuic acid and ethyl 2,4,5-trihydroxybenzoate from D-glucose.

Synthesis of catechuic acid (1) and ethyl 2,4,5-trihydroxybenzoate (2) from D-glucose-derived beta-ketoester is described. The polyhydroxylated beta-ketoester obtained from the hydrolysis of sugar beta-ketoester 3 was subjected to an aldol-type condensation to get 4 that on enolization, dehydration, and hydrogenation afforded ethyl 2,4,5-trihydroxybenzoate (2). On the other hand, hydrogenation of aldol product 4 afforded polyhydroxylated keto-carbasugar 6, which on mild acid treatment and ester hydrolysis in basic media led to catechuic acid 1.