Metal-graphite reagents in carbohydrate chemistry. 8. The scope and limitations of the use of zinc/silver-graphite in the synthesis of carbohydrate-derived substituted hex-5-enals and pent-4-enals

Abstract

The compatibility of different organic functional groups with the use of the zinc/silver-graphite reagent was investigated, utilizing 23 6-bromo-6-deoxy- or 6-deoxy-6-iodohexopyranosides and 5-deoxy-5-iodopentofuranose derivatives. These compounds possessed O-acetyl, O-benzoyl, O-methyl-, or O-p-tolylsulfonyl, O-benzyl, O-methyl, O-isopropylidene, epoxy, acetamido deoxy, azido deoxy, chloro deoxy, and deoxy fluoro groups and included a mono and a dideoxy derivative. Reductive dealkoxyhalogenation of these compounds gave, in most instances, a single product, a hex-5- or pent-4-enal, which could be considered a precursor for carbocyclization reactions