Stereocontrolled Access to Higher Sugars (Non‐1‐en‐4‐ulopyranosyl Derivatives) and Glycomimetics [3‐(β‐ D ‐Glycopyranosyl)‐1‐propenes and(3 Z )‐4,8‐Anhydro‐nona‐1,3‐dienitols]

Peracetylated 1‐bromo‐β‐ D ‐glycopyranosyl chlorides react with allyltributyltin under photolytic conditions to afford the corresponding acetylated α‐ D ‐non‐1‐en‐4‐ulopyranosyl chlorides. Yields vary, depending mainly on the parent sugar configuration ( D ‐ gluco : 86%; D ‐ galacto : 51%; D ‐ manno : 31%). The corresponding acetylated α‐ D ‐non‐1‐en‐4‐ulopyranoses resulting from hydrolysis were obtained as by‐products (8−23% yield). Radical reduction of the acetylated α‐ D ‐non‐1‐en‐4‐ulopyranosyl chlorides, mediated by n Bu 3 SnH, led to glycopyranos‐1‐yl radicals, the diastereoselective quenching of which produced acetylated 3‐(β‐ D ‐glycopyranosyl)‐1‐propenes in good overall yield (50−57% yield). This approach, which combines C−C and C−H bond forming reactions involving glycopyranosyl radicals, constitutes a more efficient route to acetylated 3‐(β‐ D ‐glycopyranosyl)‐1‐propenes. No traces of the 3‐(α‐ D ‐glycopyranosyl)‐1‐propene epimers could be detected, so the diastereoselectivity of the radical‐mediated reduction controlling the product structure was ascertained to be >95:5. On treatment with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), the acetylated 4‐ulopyranosyl chlorides underwent stereoselective dehydrochlorination to afford new (3 Z )‐4,8‐anhydronona‐1,3‐dienitols (42−63% yield), which could be deacetylated. Since these syntheses can be carried out by one‐pot procedures, this work opens up easy access to unsaturated C ‐glycopyranosyl compounds which are otherwise difficult to prepare or are completely unknown.