Preparation of various C-2 branched carbohydrates using intramolecular radical reactions Original Research Article

A new and efficient method for the facile synthesis of C-2 branched carbohydrates has been developed using an intramolecular radical cyclization–fragmentation reaction. The desired C-2 branched glucopyranosides were isolated in 40–84% yield. Additionally, an unexpected furanoside was obtained from a tributyltin iodide-promoted rearrangement of the radical intermediate. The C-2 formyl glycal was also isolated in good yield using tris(trimethylsilyl)silane (TTMSS) as the reducing agent. This method was extended to synthesize a β C-2 branched glucopyranoside, a C-2 branched galactoside and a C-2 cyano glucopyranoside.